ci: 🤖 Add formatting check for Markdown

Not sure this will work as intended

.github/workflows/format.yml

@@ -21,6 +21,25 @@ jobs:
           components: rustfmt
       - name: Check Rust formatting
         run: cargo fmt -v --all -- --check
+  remark:
+    name: Check Markdown formatting
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 9
+      - name: Install Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: "pnpm"
+      - name: Install remark
+        run: pnpm install remark-cli
+      - name: Check Markdown formatting
+        run: remark . -o
   taplo:
     name: Check TOML formatting
     runs-on: ubuntu-latest