Problem

There is a lengthy example of how to annotate angles, including a custom class to do so, at https://matplotlib.org/devdocs/gallery/text_labels_and_annotations/angle_annotation.html. This class is now being used in #24145 because annotating arrows is kind of complex and also useful.

Proposed solution

I think the class should be pulled into the library so it can be more easily reused. This would involve

• figuring out where in the library class AngleAnnotation([Arc](https://matplotlib.org/devdocs/api/_as_gen/matplotlib.patches.Arc.html#matplotlib.patches.Arc)) should go
• ensuring the annotation is scale invariant, which would fix [Doc]: Example for "Scale invariant angle label" does not scale the arc correctly #22392
• writing tests
• adding a whats new entry
• splitting up https://matplotlib.org/devdocs/gallery/text_labels_and_annotations/angle_annotation.html into reference and gallery docs