Doc: Warn that decorated methods might not be bindable. (#7010)
Doc: Warn that decorated methods might not be bindable. (#7010)

* #7007: Warn that decorated methods might not be bindable.

This is the documentation-only part of #7007, and doesn't include improvements to exception messages to reinforce this message.

* Improve description and mark-up

* Fix typo

* Apply suggestions from code review

Co-authored-by: matham <69165740e398398d3d39a23bf2a7a2fc9980d489@gmail.com>
kivy/kivy,rnixx/kivy,rnixx/kivy,matham/kivy,matham/kivy,matham/kivy,rnixx/kivy,akshayaurora/kivy,akshayaurora/kivy,kivy/kivy,akshayaurora/kivy,kivy/kivy,matham/kivy