Add linting for markdown files (#3646)

I also reworked the Linters section in `CONTRIBUTING.md` a bit and
switched the `prettier` config to a flat config.

Co-authored-by: Veeck <[email protected]>

.github/CONTRIBUTING.md

@@ -6,22 +6,28 @@ We hold our code to standard, and these standards are documented below.
 
 ## Linters
 
-We use prettier for automatic linting of all our files: `npm run lint:prettier`.
+We use [prettier](https://prettier.io/) for automatic formatting a lot all our files. The configuration is in our `prettier.config.mjs` file.
 
-### JavaScript: Run ESLint
+To run prettier, use `npm run lint:prettier`.
 
-We use [ESLint](https://eslint.org) on our JavaScript files.
+### JavaScript: Run ESLint
 
-The ESLint configuration is in our `eslint.config.mjs` file.
+We use [ESLint](https://eslint.org) to lint our JavaScript files. The configuration is in our `eslint.config.mjs` file.
 
 To run ESLint, use `npm run lint:js`.
 
 ### CSS: Run StyleLint
 
-We use [StyleLint](https://stylelint.io) to lint our CSS. Our configuration is in our `.stylelintrc` file.
+We use [StyleLint](https://stylelint.io) to lint our CSS. The configuration is in our `.stylelintrc.json` file.
 
 To run StyleLint, use `npm run lint:css`.
 
+### Markdown: Run markdownlint
+
+We use [markdownlint-cli2](https://github.com/DavidAnson/markdownlint-cli2) to lint our markdown files. The configuration is in our `.markdownlint.json` file.
+
+To run markdownlint, use `npm run markdownlint:css`.
+
 ## Testing
 
 We use [Jest](https://jestjs.io) for JavaScript testing.

.github/workflows/automated-tests.yaml

@@ -39,4 +39,5 @@ jobs:
           npm run test:prettier
           npm run test:js
           npm run test:css
+          npm run test:markdown
           npm run test

.markdownlint.json

@@ -0,0 +1,6 @@
+{
+	"line_length": false,
+	"no-duplicate-heading": false,
+	"no-inline-html": false,
+	"no-trailing-punctuation": false
+}

CHANGELOG.md

@@ -16,11 +16,12 @@ _This release is scheduled to be released on 2025-01-01._
 - [core] Add wayland and windows start options to `package.json` (#3594)
 - [docs] Add step for npm publishing in release process (#3595)
 - [core] Add GitHub workflow to run spellcheck a few days before each release (#3623)
-- [core] Add intest flag to index.html to pass to module js for test mode detection (needed by #3630)
-- [compliments] add support for refreshing remote compliments file, and testcases (#3630)
+- [core] Add test flag to index.html to pass to module js for test mode detection (needed by #3630)
+- [core] Add export on animation names (#3644)
+- [compliments] add support for refreshing remote compliments file, and test cases (#3630)
 - [linter] Re-add `eslint-plugin-import`now that it supports ESLint v9 (#3586)
-- [linter] Re-activate `eslint-plugin-package-json` to lint `package.json`
-- [core] Add export on animation names
+- [linter] Re-activate `eslint-plugin-package-json` to lint `package.json` (#3643)
+- [linter] Add linting for markdown files.
 - [calendar] - added ability to display end date for full date events, where end is not same day (showEnd=true)
 
 ### Removed

Collaboration.md

@@ -1,3 +1,5 @@
+# Collaboration
+
 This document describes how collaborators of this repository should work together.
 
 ## Pull Requests

README.md

@@ -1,14 +1,14 @@
-![MagicMirror²: The open source modular smart mirror platform. ](.github/header.png)
+# ![MagicMirror²: The open source modular smart mirror platform.](.github/header.png)
 
 <p style="text-align: center">
   <a href="https://choosealicense.com/licenses/mit">
-		<img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="License">
-	</a>
-	<img src="https://img.shields.io/github/actions/workflow/status/magicmirrororg/magicmirror/automated-tests.yaml" alt="GitHub Actions">
-	<img src="https://img.shields.io/github/check-runs/magicmirrororg/magicmirror/master" alt="Build Status">
-	<a href="https://github.com/MagicMirrorOrg/MagicMirror">
-		<img src="https://img.shields.io/github/stars/magicmirrororg/magicmirror?style=social">
-	</a>
+  <img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="License">
+ </a>
+ <img src="https://img.shields.io/github/actions/workflow/status/magicmirrororg/magicmirror/automated-tests.yaml" alt="GitHub Actions">
+ <img src="https://img.shields.io/github/check-runs/magicmirrororg/magicmirror/master" alt="Build Status">
+ <a href="https://github.com/MagicMirrorOrg/MagicMirror">
+  <img src="https://img.shields.io/github/stars/magicmirrororg/magicmirror?style=social" alt="GitHub Stars">
+ </a>
 </p>
 
 **MagicMirror²** is an open source modular smart mirror platform. With a growing list of installable modules, the **MagicMirror²** allows you to convert your hallway or bathroom mirror into your personal assistant. **MagicMirror²** is built by the creator of [the original MagicMirror](https://michaelteeuw.nl/tagged/magicmirror) with the incredible help of a [growing community of contributors](https://github.com/MagicMirrorOrg/MagicMirror/graphs/contributors).
@@ -24,7 +24,7 @@ For the full documentation including **[installation instructions](https://docs.
 - Website: [https://magicmirror.builders](https://magicmirror.builders)
 - Documentation: [https://docs.magicmirror.builders](https://docs.magicmirror.builders)
 - Forum: [https://forum.magicmirror.builders](https://forum.magicmirror.builders)
-  - Technical discussions: https://forum.magicmirror.builders/category/11/core-system
+  - Technical discussions: <https://forum.magicmirror.builders/category/11/core-system>
 - Discord: [https://discord.gg/J5BAtvx](https://discord.gg/J5BAtvx)
 - Blog: [https://michaelteeuw.nl/tagged/magicmirror](https://michaelteeuw.nl/tagged/magicmirror)
 - Donations: [https://magicmirror.builders/#donate](https://magicmirror.builders/#donate)
@@ -49,5 +49,5 @@ If we receive enough donations we might even be able to free up some working hou
 To donate, please follow [this](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=G5D8E9MR5DTD2&source=url) link.
 
 <p style="text-align: center">
-	<a href="https://forum.magicmirror.builders/topic/728/magicmirror-is-voted-number-1-in-the-magpi-top-50"><img src="https://magicmirror.builders/img/magpi-best-watermark-custom.png" width="150" alt="MagPi Top 50"></a>
+  <a href="https://forum.magicmirror.builders/topic/728/magicmirror-is-voted-number-1-in-the-magpi-top-50"><img src="https://magicmirror.builders/img/magpi-best-watermark-custom.png" width="150" alt="MagPi Top 50"></a>
 </p>

cspell.config.json

@@ -198,6 +198,7 @@
 		"tada",
 		"taglist",
 		"Teeuw",
+		"TESTMODE",
 		"thomasrockhu",
 		"tomzt",
 		"ukmetoffice",