Add CI check to ensure docs build without warnings (#558)

Closes #554

Author: kylebarron

.github/workflows/test.yml

@@ -79,6 +79,11 @@ jobs:
       - name: Run tests
         run: poetry run pytest
 
+      # Ensure docs build without warnings
+      - name: Check docs
+        if: matrix.python-version == 3.9
+        run: poetry run mkdocs build --strict
+
       - name: Cache pre-commit virtualenvs
         uses: actions/cache@v4
         if: matrix.python-version == 3.9