build docs on CI and deny warnings

.github/workflows/ci.yaml

@@ -325,6 +325,8 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
       - name: install ruff
         run: python -m pip install ruff==0.0.291 # astral-sh/ruff#7778
+      - name: Ensure docs generate no warnings
+        run: cargo doc -- -Dwarnings
       - name: run python lint
         run: ruff extra_tests wasm examples  --exclude='./.*',./Lib,./vm/Lib,./benches/ --select=E9,F63,F7,F82 --show-source
       - name: install prettier