gh-87961: Remove outdated notes from functions that aren't in the Limited API (GH-93581) (GH-93605)

Nowadays everything that *is* in the Limited API has a note added
automatically.
These notes could mislead people to think that these functions
could never be added to the limited API. Remove them.

(cherry picked from commit 2c3fe5eeb2b64deb2132d9259e74b521c14fd92d)

Co-authored-by: Petr Viktorin <encukou@gmail.com>