[doc] Mention __slots__ behavior in weakref.rst - #21061

[doc] Mention __slots__ behavior in weakref.rst#21061

ambv merged 2 commits into

python:mainpython/cpython:mainfrom

jstasiak:mention-slots-in-weakref-docsjstasiak/cpython:mention-slots-in-weakref-docsCopy head branch name to clipboard