gh-107006: Move threading.local docstring to docs

[lysnikolaou]

Move threading.local docs from its docstring to the docs. Especially now that threading.local will become more widely used due to free-threading, having a quick how-to in the docs is going to be very helpful.

• Issue: Move threading.local docs from docstring to the docs #107006

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📚 Documentation preview 📚: https://cpython-previews--131840.org.readthedocs.build/

[python-cla-bot]

All commit authors signed the Contributor License Agreement.

[hugovk]

Thank you!

[miss-islington-app]

Thanks @lysnikolaou for the PR, and @hugovk for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-133432 is a backport of this pull request to the 3.13 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Windows11 Bigmem 3.x (tier-1) has failed when building commit b97328e.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1079/builds/6436) and take a look at the build logs.
4. Check if the failure is related to this commit (b97328e) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1079/builds/6436

Failed tests:

• test_frame

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 143, in _print_exception_bltin
    return print_exception(exc, limit=BUILTIN_EXCEPTION_LIMIT, file=file, colorize=colorize)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 134, in print_exception
    te.print(file=file, chain=chain, colorize=colorize)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 1577, in print
    for line in self.format(chain=chain, colorize=colorize):
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 1514, in format
    yield from _ctx.emit(exc.format_exception_only(colorize=colorize))
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 1001, in emit
    for text in text_gen:
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\traceback.py", line 1268, in format_exception_only
    isinstance(self.__notes__, collections.abc.Sequence)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\abc.py", line 119, in __instancecheck__
    return _abc_instancecheck(cls, instance)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\abc.py", line 123, in __subclasscheck__
    return _abc_subclasscheck(cls, subclass)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\abc.py", line 123, in __subclasscheck__
    return _abc_subclasscheck(cls, subclass)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\abc.py", line 123, in __subclasscheck__
    return _abc_subclasscheck(cls, subclass)
RecursionError: Stack overflow (used 11719 kB)


Traceback (most recent call last):
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\test\support\os_helper.py", line 524, in temp_dir
    os.mkdir(path)
    ~~~~~~~~^^^^^^
FileExistsError: [WinError 183] Cannot create a file when that file already exists: 'R:\\buildarea\\3.x.ambv-bb-win11.bigmem\\build\\build\\test_python_9472�'
Stack (most recent call last):
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\runpy.py", line 198, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\runpy.py", line 88, in _run_code
    exec(code, run_globals)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\test\libregrtest\worker.py", line 131, in <module>
    main()
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\test\libregrtest\worker.py", line 126, in main
    with os_helper.temp_cwd(work_dir, quiet=True):
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\contextlib.py", line 141, in __enter__
    return next(self.gen)
  File "R:\buildarea\3.x.ambv-bb-win11.bigmem\build\Lib\test\support\os_helper.py", line 597, in temp_cwd
    with temp_dir(path=name, quiet=quiet) as temp_path:

[hugovk]

The buildbot test_frame failure is unrelated, should be fixed in #133261.