gh-101100: Fix Sphinx warnings in whatsnew/3.9.rst

[hugovk]

Fix 34 warnings in whatsnew/3.9.rst:

whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _abc
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _bz2
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _codecs
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _contextvars
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _functools
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _json
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _locale
whatsnew/3.9.rst:84: WARNING: py:mod reference target not found: _weakref
whatsnew/3.9.rst:89: WARNING: py:mod reference target not found: _hashlib
whatsnew/3.9.rst:89: WARNING: py:mod reference target not found: _posixsubprocess
whatsnew/3.9.rst:205: WARNING: py:mod reference target not found: parser
whatsnew/3.9.rst:369: WARNING: py:exc reference target not found: TyperError
whatsnew/3.9.rst:592: WARNING: py:attr reference target not found: si_code
whatsnew/3.9.rst:864: WARNING: py:mod reference target not found: parser
whatsnew/3.9.rst:864: WARNING: py:mod reference target not found: symbol
whatsnew/3.9.rst:892: WARNING: py:class reference target not found: _tkinter.TkappType
whatsnew/3.9.rst:901: WARNING: py:mod reference target not found: binhex
whatsnew/3.9.rst:904: WARNING: py:func reference target not found: binascii.b2a_hqx
whatsnew/3.9.rst:904: WARNING: py:func reference target not found: binascii.a2b_hqx
whatsnew/3.9.rst:905: WARNING: py:func reference target not found: binascii.rlecode_hqx
whatsnew/3.9.rst:905: WARNING: py:func reference target not found: binascii.rledecode_hqx
whatsnew/3.9.rst:953: WARNING: py:data reference target not found: unittest.mock.__version__
whatsnew/3.9.rst:990: WARNING: py:meth reference target not found: threading.Thread.isAlive
whatsnew/3.9.rst:1038: WARNING: py:func reference target not found: sys.getcounts
whatsnew/3.9.rst:1049: WARNING: py:meth reference target not found: symtable.SymbolTable.has_exec
whatsnew/3.9.rst:1053: WARNING: py:meth reference target not found: asyncio.Task.current_task
whatsnew/3.9.rst:1053: WARNING: py:meth reference target not found: asyncio.Task.all_tasks
whatsnew/3.9.rst:1233: WARNING: c:func reference target not found: setenv
whatsnew/3.9.rst:1233: WARNING: c:func reference target not found: unsetenv
whatsnew/3.9.rst:1322: WARNING: c:func reference target not found: _PyObject_FunctionStr
whatsnew/3.9.rst:1364: WARNING: c:type reference target not found: PyGC_Head
whatsnew/3.9.rst:1387: WARNING: c:func reference target not found: PyObject_NEW
whatsnew/3.9.rst:1387: WARNING: c:func reference target not found: PyObject_NEW_VAR
whatsnew/3.9.rst:1392: WARNING: c:func reference target not found: PyObject_GET_WEAKREFS_LISTPTR

Plus related fixes in other files.

These 6 remain, which could benefit from being documented, will leave for a later decision:

whatsnew/3.9.rst:426: WARNING: py:const reference target not found: fcntl.F_OFD_GETLK
whatsnew/3.9.rst:426: WARNING: py:const reference target not found: fcntl.F_OFD_SETLK
whatsnew/3.9.rst:426: WARNING: py:const reference target not found: fcntl.F_OFD_SETLKW
whatsnew/3.9.rst:646: WARNING: py:attr reference target not found: random.Random.randbytes
whatsnew/3.9.rst:778: WARNING: py:func reference target not found: set.difference_update
whatsnew/3.9.rst:1140: WARNING: py:func reference target not found: encodings.normalize_encoding

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

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📚 Documentation preview 📚: https://cpython-previews--118364.org.readthedocs.build/

[miss-islington-app]

Thanks @hugovk for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[miss-islington-app]

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

cherry_picker e0ab6424369bcd276b0dc4f537fde360bdca2f05 3.12

[bedevere-app]

GH-118365 is a backport of this pull request to the 3.12 branch.