ci(markdownlint): add Markdown linting (reanahub#838)

Author: jlemesh

.github/workflows/ci.yml

@@ -193,3 +193,17 @@ jobs:
         run: |
           pip install yamllint
           ./run-tests.sh --check-yamllint
+
+  lint-markdownlint:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+
+      - name: Lint Markdown files
+        run: |
+          npm install markdownlint-cli2
+          ./run-tests.sh --check-markdownlint

.markdownlint.yaml

@@ -0,0 +1,11 @@
+# MD013/line-length : Line length : https://github.com/DavidAnson/markdownlint/blob/v0.35.0/doc/md013.md
+MD013: false
+
+# MD037/no-space-in-emphasis : Spaces inside emphasis markers : https://github.com/DavidAnson/markdownlint/blob/v0.35.0/doc/md037.md
+MD037: false
+
+# MD041/first-line-heading/first-line-h1 : First line in a file should be a top-level heading : https://github.com/DavidAnson/markdownlint/blob/v0.35.0/doc/md041.md
+MD041: false
+
+# MD043/required-headings : Required heading structure : https://github.com/DavidAnson/markdownlint/blob/v0.35.0/doc/md043.md
+MD043: false