docs: update vsc-extension-quickstart.md

CONTRIBUTING.md

@@ -28,3 +28,33 @@ yarn release
 # to manually publish the extension
 yarn env-cmd && yarn publish
 ```
+
+# VS Code Extension Quickstart
+
+## What's in the folder
+
+* This folder contains all of the files necessary for your extension.
+* `package.json` - this is the manifest file in which you declare your language support and define the location of the grammar file that has been copied into your extension.
+* `syntaxes/nix.YAML-tmLanguage` - this is the Text mate grammar file that is used for tokenization. This will get compiled to `syntaxes/nix.tmLanguage.json` during build.
+* `language-configuration.json` - this is the language configuration, defining the tokens that are used for comments and brackets.
+
+## Get up and running straight away
+
+* Make sure the language configuration settings in `language-configuration.json` are accurate.
+* Press `F5` to open a new window with your extension loaded.
+* Create a new file with a file name suffix matching your language.
+* Verify that syntax highlighting works and that the language configuration settings are working.
+
+## Make changes
+
+* You can relaunch the extension from the debug toolbar after making changes to the files listed above.
+* You can also reload ( `Ctrl+R` or `Cmd+R` on Mac) the VS Code window with your extension to load your changes.
+
+## Add more language features
+
+* To add features such as intellisense, hovers and validators check out the VS Code extenders documentation at https://code.visualstudio.com/docs
+
+## Install your extension
+
+* To start using your extension with Visual Studio Code copy it into the `<user home>/.vscode/extensions` folder and restart Code.
+* To share your extension with the world, read on https://code.visualstudio.com/docs about publishing an extension.