gh-101100: Fix Sphinx warnings in Doc/library/weakref.rst

[sobolevn]

It used to be:

/Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:112: WARNING: py:meth reference target not found: __del__ /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:223: WARNING: py:meth reference target not found: keyrefs /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:281: WARNING: py:meth reference target not found: __del__ /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:526: WARNING: py:meth reference target not found: __del__ /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:534: WARNING: py:meth reference target not found: remove /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:537: WARNING: py:meth reference target not found: __del__ /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:556: WARNING: py:meth reference target not found: __del__ /Users/sobolev/Desktop/cpython/Doc/library/weakref.rst:561: WARNING: py:meth reference target not found: __del__ 

• Issue: Fix all Sphinx reference warnings in the documentation #101100

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📚 Documentation preview 📚: https://cpython-previews--109881.org.readthedocs.build/

[hugovk]

Thanks!

[miss-islington]

Thanks @sobolevn for the PR, and @hugovk for merging it 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

[miss-islington]

Sorry, @sobolevn and @hugovk, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker 7c61a361fc2e93375e22849fffbc20b60e94dbde 3.12

[bedevere-app]

GH-109883 is a backport of this pull request to the 3.11 branch.

[bedevere-app]

GH-109884 is a backport of this pull request to the 3.12 branch.