put fail on warning for the sphinx_limit workflow

Author: rocco8773

.github/workflows/documentation.yml

@@ -76,6 +76,6 @@ jobs:
           sudo apt-get install graphviz pandoc
       - name: Build Docs
         run: |
-          sphinx-build ./docs ./docs/_build -n --keep-going -b html -q
+          sphinx-build ./docs ./docs/_build -n --keep-going -W -b html -q