Set warnings as errors, temporarily

Author: aidanfnv

.github/workflows/sphinx-build-test.yml

@@ -29,7 +29,7 @@ jobs:
           cd docs
           # Run Sphinx build to catch issues
           # -D build_toctree=True enables toctree processing to verify all docs are included
-          python -m sphinx -b html . _build/html
+          python -m sphinx -W -b html . _build/html
 
       - name: Check for broken links to external sites
         run: |