[3.13] GH-65961: Document the deprecation of `__package__` and `__cached__` (GH-124377) (#124380)
* GH-65961: Document the deprecation of `__package__` and `__cached__` (GH-124377)
The code changes for warning related to `__package__` landed in Python 3.12. `__cached__` doesn't have any changes as it isn't used but only set by the import system.
(cherry picked from commit 67201ad53ff11576c69a9b762540b77128285f8d)
---------
Co-authored-by: Brett Cannon <brett@python.org>
Co-authored-by: Barry Warsaw <barry@python.org>
4 files changed
