Fixed minor Typos and grammatical errors (#9353)

Fixed some typos and grammatical errors in docs/docs

Contributed as a part of Hacktoberfest 2018

docs/docs/add-a-manifest-file.md

@@ -8,11 +8,11 @@ But first, what exactly _are_ PWAs?
 
 They are regular websites that take advantage of modern browser functionality to augment the web experience with app-like features and benefits. Check out [Google's overview](https://developers.google.com/web/progressive-web-apps/) of what defines a PWA experience and the [Progressive web apps (PWAs) doc](/docs/progressive-web-app/) to learn how a Gatsby site is a progressive web app.
 
-Inclusion of a web app manifest is one of the three generally accepted [baseline requirements for a PWA](https://alistapart.com/article/yes-that-web-project-should-be-a-pwa#section1).
+The inclusion of a web app manifest is one of the three generally accepted [baseline requirements for a PWA](https://alistapart.com/article/yes-that-web-project-should-be-a-pwa#section1).
 
 Quoting [Google](https://developers.google.com/web/fundamentals/web-app-manifest/):
 
-> The web app manifest is a simple JSON file that tells the browser about your web application and how it should behave when 'installed' on the users mobile device or desktop.
+> The web app manifest is a simple JSON file that tells the browser about your web application and how it should behave when 'installed' on the user's mobile device or desktop.
 
 [Gatsby's manifest plugin](/packages/gatsby-plugin-manifest/) configures Gatsby to create a `manifest.webmanifest` file on every site build.
 

docs/docs/adding-analytics.md

@@ -30,7 +30,7 @@ You can find this tracking ID later by going to `Admin > Tracking Info > Trackin
 
 Now, it's time to configure Gatsby to send page views to your Google Analytics account.
 
-We are going to use `gatsby-plugin-google-analytics`. For other analytics options (including Google Analytics gtag.js ang Google Tag Manager), check [other Gatsby analytics plugins](#other-gatsby-analytics-plugins).
+We are going to use `gatsby-plugin-google-analytics`. For other analytics options (including Google Analytics gtag.js and Google Tag Manager), check [other Gatsby analytics plugins](#other-gatsby-analytics-plugins).
 
 ```bash
 npm install --save gatsby-plugin-google-analytics

docs/docs/adding-images-fonts-files.md

@@ -123,7 +123,7 @@ However, there is an **escape hatch** that you can use to add an asset outside o
 the module system.
 
 If you put a file into the `static` folder, it will **not** be processed by
-Webpack. Instead it will be copied into the public folder untouched. E.g. if you
+Webpack. Instead, it will be copied into the public folder untouched. E.g. if you
 add a file named `sun.jpg` to the static folder, it'll be copied to
 `public/sun.jpg`. To reference assets in the `static` folder, you'll need to
 [import a helper function from `gatsby` named `withPrefix`](/docs/gatsby-link/#prefixed-paths-helper).

docs/docs/adding-markdown-pages.md

@@ -5,7 +5,7 @@ title: Adding Markdown Pages
 Gatsby can use markdown files to create pages in your site.
 You add plugins to read and understand folders with markdown files and from them create pages automatically.
 
-Here's the steps Gatsby follows for making this happen.
+Here are the steps Gatsby follows for making this happen.
 
 1.  Read files into Gatsby from the filesystem
 2.  Transform markdown to HTML and frontmatter to data

docs/docs/adding-tags-and-categories-to-blog-posts.md

@@ -42,7 +42,7 @@ If `gatsby develop` is running, restart it so Gatsby can pick up the new fields.
 
 ## Write a query to get all tags for your posts
 
-Now these fields are available in the data layer. To use field data, query it using `graphql`. All fields are available to query inside `frontmatter`
+Now, these fields are available in the data layer. To use field data, query it using `graphql`. All fields are available to query inside `frontmatter`
 
 Try running in Graph<em>i</em>QL (`localhost:8000/___graphql`) the following query
 

docs/docs/api-proxy.md

@@ -26,8 +26,8 @@ the right place in production.
 
 ## Advanced proxying
 
-Sometimes you need more granular/flexible access to the develop server.
-Gatsby exposes the [Express.js](https://expressjs.com/) develop server to your site's `gatsby-config.js` where you
+Sometimes you need more granular/flexible access to the development server.
+Gatsby exposes the [Express.js](https://expressjs.com/) development server to your site's `gatsby-config.js` where you
 can add Express middleware as needed.
 
 ```javascript:title=gatsby-config.js

docs/docs/api-specification.md

@@ -44,7 +44,7 @@ highlighting to code blocks.
 Transformer plugins are decoupled from source plugins. Transformer plugins look
 at the media type of new nodes created by source plugins to decide if they can
 transform it or not. Which means that a markdown transformer plugin can
-transform markdown from any source without any other configuration e.g. from
+transform markdown from any source without any other configuration e.g. from a
 file, a code comment, or external service like Trello which supports markdown
 in some of its data fields.
 
@@ -97,15 +97,15 @@ fin
 Once the initial bootstrap is finished, we start `webpack-dev-server` and an express server for serving files for the development server, and for a production build, we start building the CSS then JavaScript then HTML with webpack.
 
 During these processes there are various extension points where plugins can
-intervene. All major processes have a `onPre` and `onPost` e.g. `onPreBootstrap`
+intervene. All major processes have an `onPre` and `onPost` e.g. `onPreBootstrap`
 and `onPostBootstrap` or `onPreBuild` or `onPostBuild`. During bootstrap,
 plugins can respond at various stages to APIs like `onCreatePages`,
 `onCreateBabelConfig`, and `onSourceNodes`.
 
 At each extension point, Gatsby identifies the plugins which implement the API
 and calls them in serial following their order in the site's `gatsby-config.js`.
 
-In addition to extension APIs in node, plugins can also implement extension APIs
+In addition to extension APIs in a node, plugins can also implement extension APIs
 in the server rendering process and the browser e.g. `onClientEntry` or
 `onRouteUpdate`
 

docs/docs/babel.md

@@ -8,7 +8,7 @@ support for writing modern JavaScript — while still supporting older browsers.
 ## How to specify which browsers to support
 
 Gatsby supports by default the last two versions of major browsers, IE 9+, as well as
-any browser that still as 1%+ browser share.
+any browser that still has 1%+ browser share.
 
 This means we automatically compile your JavaScript to ensure it works on older browsers.
 We also automatically add polyfills as needed — no more shipping code which mysteriously

docs/docs/behind-the-scenes-terminology.md

@@ -43,7 +43,7 @@ It is also used by [gatsby-plugin-netlify](/packages/gatsby-plugin-netlify/?=net
 
 ### jsonName
 
-The logical name for the page's query json result. The name is constructed during [createPage](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby/src/redux/actions.js#L229) using a kebabHash of page path. E.g. For above page path, it is:
+The logical name for the page's query json result. The name is constructed during [createPage](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby/src/redux/actions.js#L229) using a kebabHash of page path. E.g. For the above page path, it is:
 
 `blog-2018-07-17-announcing-gatsby-preview-995`
 

docs/docs/building-with-components.md

@@ -118,7 +118,7 @@ export const pageQuery = graphql`
 `src/html.jsx` is responsible for everything other than where Gatsby lives in
 the `<body />`.
 
-In this file you can modify the `<head>` metadata, general structure of the
+In this file, you can modify the `<head>` metadata and general structure of the
 document and add external links.
 
 Typically you should omit this from your site as the default html.js file will

docs/docs/centralizing-your-sites-navigation.md

@@ -42,11 +42,11 @@ module.exports = {
 
 ### Viewing the `siteMetadata` in GraphQL
 
-GraphQL can be used to query for information contained in the `siteMetadata` object located in your project's `gatsby-config.js`. In order to test this out you can start the `default-starter-project` in development mode by running `npm run develop`.
+GraphQL can be used to query for information contained in the `siteMetadata` object located in your project's `gatsby-config.js`. In order to test this out, you can start the `default-starter-project` in development mode by running `npm run develop`.
 
 Navigate to `http://localhost:8000/___graphql` in your browser to view the GraphiQL editor, which enables you to test GraphQL queries on the underlying APIs. Using the documentation explorer you can view the current GraphQL schema for your project, which is an invaluable resource during development.
 
-Examining the available types in GraphQL you will notice that you can query `site`. This GraphQL type further returns the `siteMetadata` which needs to be accessed to create the dynamic navigation. At this point it is useful if you know a little GraphQL in order to extract the menu links. If you are unfamiliar with GraphQL, there is some excellent documentation available at GraphQL's official website found [here](https://graphql.org/learn/) tha you can use to brush up on your skills! The query below will return the menu links.
+Examining the available types in GraphQL you will notice that you can query `site`. This GraphQL type further returns the `siteMetadata` which needs to be accessed to create the dynamic navigation. At this point, it is useful if you know a little GraphQL in order to extract the menu links. If you are unfamiliar with GraphQL, there is some excellent documentation available at GraphQL's official website found [here](https://graphql.org/learn/) that you can use to brush up on your skills! The query below will return the menu links.
 
 ```js
 query SiteQuery {
@@ -90,7 +90,7 @@ Perfect! You now have a way of obtaining data from the `gatsby-config.js` file.
 
 ### Pulling data inside the layout component
 
-Inside your project, locate the `src/components` folder and navigate to the `layout.js` file. Within this layout component you should notice a component named `StaticQuery`.
+Inside your project, locate the `src/components` folder and navigate to the `layout.js` file. Within this layout component, you should notice a component named `StaticQuery`.
 
 StaticQuery is a new component introduced in Gatsby V2, which allows you to run GraphQL queries within your components, not just pages. It allows developers to collocate data with their components.
 
@@ -141,7 +141,7 @@ const Layout = ({ children }) => (
 
 With the above changes to your `StaticQuery` component, the `render` property, which accepts a function that takes one argument, now has access to the menu links for use inside the function (as the argument). The last thing that is left to do is to display the site's navigation.
 
-To do this, the header component that is already available in the project seems like it might be a good starting place to display the navigation. Lets pass the `menuLinks` object to this header component like so:
+To do this, the header component that is already available in the project seems like it might be a good starting place to display the navigation. Let's pass the `menuLinks` object to this header component like so:
 
 ```diff:title=src/components/layout.js
 const Layout = ({ children }) => (

docs/docs/create-source-plugin.md

@@ -44,7 +44,7 @@ node for the markdown content and set its mediaType as `text/markdown` and the
 various Gatsby markdown transformer plugins will see your node and transform it
 into HTML.
 
-This loose coupling between data source and transformer plugins allow Gatsby
+This loose coupling between the data source and the transformer plugins allow Gatsby
 site builders to quickly assemble complex data transformation pipelines with
 little work on their (and your (the source plugin author)) part.
 
@@ -54,7 +54,7 @@ A source plugin is a normal NPM package. It has a package.json with optional
 dependencies as well as a `gatsby-node.js` where you implement Gatsby's Node.js
 APIs. Gatsby supports node versions back to Node 4 and as it's common to want to
 use more modern Node.js and JavaScript syntax, many plugins write code in a
-`src` directory and compile the code. All plugins maintained in the Gatsby repo
+source directory and compile the code. All plugins maintained in the Gatsby repo
 follow this pattern.
 
 Your `gatsby-node.js` should look something like:
@@ -110,7 +110,7 @@ There are two ways of adding node relationships in Gatsby: (1) transformations (
 
 An example of a transformation relationship is the `gatsby-transformer-remark` plugin, which transforms a parent `fileNode`'s markdown string into a `MarkdownRemark` node. The Remark transformer plugin adds its newly created child node as a child of the parent node using the action `createParentChildLink`. Transformation relationships are used when a new node is _completely_ derived from a single parent node. E.g. the markdown node is derived from the parent `fileNode` and wouldn't ever exist if the parent `fileNode` hadn't been created.
 
-Because all children nodes are derived from their parent, when a parent node is deleted or changed, Gatsby deletes all of the child nodes (and their child nodes, and so on) with the expectation that they'll be recreated again by transformer plugins. This is done to ensure there's not nodes left over that were derived from older versions of data but shouldn't exist any longer.
+Because all children nodes are derived from their parent, when a parent node is deleted or changed, Gatsby deletes all of the child nodes (and their child nodes, and so on) with the expectation that they'll be recreated again by transformer plugins. This is done to ensure there are no nodes left over that were derived from older versions of data but shouldn't exist any longer.
 
 _Creating the transformation relationship_
 

docs/docs/create-transformer-plugin.md

@@ -35,9 +35,9 @@ Information on the purpose of this function can be found in the [API reference](
 
 ## Using the cache
 
-Sometimes transforming properties costs time and resources and in order to avoid recreating these properties at each run you can profit from the global cache mechanism Gatsby provides.
+Sometimes transforming properties costs time and resources. In order to avoid recreating these properties at each run, you can profit from the global cache mechanism Gatsby provides.
 
-Cache keys should at least contain the contentDigest of the concerned. For example the `gatsby-transformer-remark` uses the following cache key for the html node:
+Cache keys should at least contain the contentDigest of the concerned. For example, the `gatsby-transformer-remark` uses the following cache key for the html node:
 
 ```javascript:title=extend-node-type.js
 const htmlCacheKey = node =>