allow warnings in sphinx builds

Author: rmorshea

scripts/test.sh

@@ -5,4 +5,4 @@ pytest src/py/tests --headless --cov=idom --cov-fail-under=82
 black --verbose --check src/py
 flake8 src/py
 mypy src/py/idom
-sphinx-build -W -b html src/py/docs/source src/py/docs/build
+sphinx-build -b html src/py/docs/source src/py/docs/build