Google docstrings + discovered issues (#2264)

* conf.py: Document the docstring callback function

* stash changes

* Various docs tweaks

* Sort imports

* More work on application docstrings

* More work on application.py

* More docstring cleanup in application

* Debug test runner

* Don't try to do any magic in set_min/max size

Author: einarf

.github/workflows/selfhosted_runner.yml

@@ -45,7 +45,7 @@ jobs:
           which python
           python -c "import pyglet; print('pyglet version', pyglet.__version__)"
           python -c "import PIL; print('Pillow version', PIL.__version__)"
-          pytest
+          pytest --maxfail=1
 
       # Prepare the Pull Request Payload artifact. If this fails, we
       # we fail silently using the `continue-on-error` option. It's