ci: improve panvimdoc workflow

.github/workflows/panvimdoc.yml

@@ -0,0 +1,39 @@
+name: panvimdoc
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - README.md
+      - .github/workflows/panvimdoc.yml
+  workflow_dispatch: {} # allows manual execution
+
+permissions:
+  contents: write
+
+#───────────────────────────────────────────────────────────────────────────────
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    name: README.md to vimdoc
+    steps:
+      - uses: actions/checkout@v4
+      - run: git pull # fix failure when multiple commits are pushed in succession
+      - run: mkdir -p doc
+
+      - name: panvimdoc
+        uses: kdheepak/panvimdoc@main
+        with:
+          vimdoc: ${{ github.event.repository.name }}
+          version: "Neovim"
+          demojify: true
+          treesitter: true
+          toc: false # already has a table of contents in the README
+
+      - run: git pull
+      - name: push changes
+        uses: stefanzweifel/git-auto-commit-action@v5
+        with:
+          commit_message: "chore: auto-generate vimdocs"
+          branch: ${{ github.head_ref }}