Adding a @_api.make_keyword_only to a method that has a pyplot wrapper fails.

make_keyword_only currently doesn't work with functions that have pyplot wrappers, because make_keyword_only fakes the displayed function signature to pretend that the switch to kwonly already occurred, but the pyplot wrapper should be generated using the old (non-kwonly) signature, but that's not the case right now.
It's going to be slightly annoying to fix but probably just needs some wrangling, can you open a separate issue to track this? In any case I don't think this is required for this PR.

Originally posted by @anntzer in #18782 (comment)