ci: show warning when docs have uncommited changes

.github/workflows/generate.yml

@@ -58,3 +58,20 @@ jobs:
         add: docs/devenv.schema.json
         message: 'Auto generate docs/devenv.schema.json'
 
+    - name: Check for uncommitted changes
+      run: |
+        diff=$(git diff --stat)
+        if [[ -n "$diff" ]]; then
+          message="There are uncommitted doc changes in the repository.
+
+          ${diff}
+
+          You can:
+            a. Run the failing devenv-generate-* commands locally and commit the changes.
+            b. Let CI auto-commit the changes to your fork of the repo."
+
+          echo "::error::${message//$'\n'/%0A}"
+          exit 1
+        else
+          echo "No uncommitted doc changes found."
+        fi