scripts: new linter script to detect goal_src files with trailing whitespace (#3387)

Removes trailing whitespace from goal_src files, eventually the
formatter will do this as well but it's not ready yet so this is a
decent interim solution.

A competent text editor will also do this / flag it for you.

.github/workflows/linting.yaml

@@ -41,6 +41,9 @@ jobs:
       - name: Checkout Repository
         uses: actions/checkout@v4
 
+      - name: Check for Trailing Whitespace in goal_src
+        run: python ./scripts/ci/lint-trailing-whitespace.py
+
       - name: Check for Unresolved Conflicts
         run: python ./scripts/gsrc/check-for-conflicts.py