Remaining issues in API documentation

[cbrnr]

Our API documentation looks very nice except for the following issues (left over from #126):

• The "See Also" section should not be listed in the left TOC
• The "Warnings" section should not be listed in the left TOC

These issues can only be addressed upstream (in griffe and python-handler repos) by adding support for "See Also", "Warnings", "Notes", and "References", see e.g. here.