Ensure optional annotations are not set to None

[robrap]

Ensure optional annotations are not set to None (and possible "n/a"). Instead, the annotation should just be dropped altogether if not needed. This applies to specific annotations where None is not a valid value (e.g. toggle_warning).

This just leads to messy docs that could be cleaner, so it us unlikely to be as urgent as other issues.

See example of where None is copied often and leads to a lot of extra code and useless docs.