github-action: add supported GitHub commands

.github/workflows/github-commands-comment.yml

@@ -0,0 +1,38 @@
+---
+name: github-commands-comment
+
+on:
+  pull_request_target:
+    types:
+      - opened
+
+permissions:
+  contents: read
+
+jobs:
+  comment:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        with:
+          script: |
+            const body = `
+              ### :robot: GitHub comments
+
+              <details><summary>Expand to view the GitHub comments</summary>
+              <p>
+
+              Just comment with:
+              - `run` `docs-build` : Re-trigger the docs validation. (use unformatted text in the comment!)
+              </p>
+              </details>
+            `.replace(/  +/g, '')
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: body
+            })