cleanup and debug

Author: blink1073

.github/workflows/build.yml

@@ -49,7 +49,7 @@ jobs:
         working-directory: jupyter-widget-testwidgets/docs
         run: |
           sudo apt install -y pandoc
-          make html
+          make html SPHINXOPTS="-W"
           python -m pytest --check-links
 
       - name: Validate extension usage
@@ -61,6 +61,7 @@ jobs:
           # Validate labextension
           pip install -U jupyterlab~=3.0
           # Make sure our lab extension was installed.
+          jupyter labextension list
           jupyter labextension list 2>&1 | grep -ie "jupyter-widget-testwidgets.*OK"
           # Make sure our lab extension can be develop installed.
           jupyter labextension develop . --overwrite

{{cookiecutter.github_project_name}}/docs/source/conf.py

@@ -88,7 +88,7 @@
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.