README: Replace git.io shortlink with full link

git.io is deprecated, so use the full link to docs.github.com instead.

README.md

@@ -67,7 +67,7 @@ jobs:
         uses: github/codeql-action/autobuild@v2
 
       # ℹ️ Command-line programs to run using the OS shell.
-      # 📚 https://git.io/JvXDl
+      # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
 
       # ✏️ If the Autobuild fails above, remove it and uncomment the following
       #    three lines and modify them (or add more) to build your code if your