Python 3.15 support

[Shogo Yamazaki (mocknen)]

Actually, this is not a feature request nor a question. However, since Python 3.15.0 final is scheduled to be released on this weekend [1], I thought creating a discussion thread to track the status would be beneficial for those that are looking for its support, like there was for 3.14 [2].

[1]: https://peps.python.org/pep-0790/
[2]: #26309

[Shogo Yamazaki (mocknen)]

#33271
#33359