ci: lint and normalize Markdown documentation

Author: megabyde

.github/workflows/main.yml

@@ -13,6 +13,11 @@ jobs:
     steps:
       - uses: actions/checkout@v7
 
+      - name: Lint Markdown
+        uses: DavidAnson/markdownlint-cli2-action@v23
+        with:
+          globs: "**/*.md"
+
       - uses: actions/setup-python@v7
         with:
           python-version: "3.11"

.markdownlint.json

@@ -0,0 +1,8 @@
+{
+  "MD013": {
+    "line_length": 100
+  },
+  "MD024": {
+    "siblings_only": true
+  }
+}