Create workflow to lint Markdown files (robolectric#265)

.github/workflows/lint-markdown.yml

@@ -0,0 +1,27 @@
+name: "Lint Markdown"
+
+on:
+  merge_group:
+  pull_request:
+  push:
+    branches: [ master ]
+
+jobs:
+  lint_project:
+    name: "Lint Markdown"
+    runs-on: ubuntu-latest
+    permissions:
+      statuses: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Lint Markdown
+        uses: DavidAnson/markdownlint-cli2-action@v16
+        with:
+          config: ".markdownlint.jsonc"
+          globs: |
+            "docs/**/*.md"
+            "#docs/javadoc/**/*.md"

.markdownlint.jsonc

@@ -0,0 +1,12 @@
+// https://github.com/DavidAnson/markdownlint/blob/main/schema/.markdownlint.jsonc
+{
+  // Line length: https://github.com/DavidAnson/markdownlint/blob/main/doc/md013.md
+  "MD013": {
+    "line_length": 120,
+    "heading_line_length": 120,
+    "code_block_line_length": 120,
+    "tables": false
+  },
+  // Code block style: https://github.com/DavidAnson/markdownlint/blob/main/doc/md046.md
+  "MD046": false
+}

README.md

@@ -6,6 +6,8 @@ This repository contains the source of the documentation that lives at [robolect
 
 Make sure that you are on the `master` branch, and that it is up to date before making any changes. This is the default branch, so Git should put you there automatically.
 
+### Build the documentation locally
+
 Before submitting a Pull Request, run the documentation locally to check that the content and layout are correct. The documentation is built using [MkDocs](https://www.mkdocs.org/).
 
 To do so, make sure that you have [Python 3+ installed](https://www.python.org/downloads/), and then install the required dependencies by running:
@@ -20,6 +22,16 @@ Then you can execute the following command to access the documentation locally a
 mkdocs serve --open
 ```
 
+### Validate your Markdown files
+
+If you modified any Markdown file, we recommend using [`DavidAnson/markdownlint-cli2`](https://github.com/DavidAnson/markdownlint-cli2) to ensure that the formatting rules are respected.
+
+Once installed, you can run the command below to perform the check. Add the `--fix` option to fix issues that can be addressed automatically. The non-resolved issues will be printed in the console.
+
+```bash
+markdownlint-cli2 "docs/**/*.md" "#docs/javadoc/**/*.md" --config .markdownlint.jsonc
+```
+
 Once your Pull Request is merged, the documentation will be automatically built and deployed by GitHub Actions.
 
 ## Javadocs