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

[hugovk]

Fix 6 warnings:

Doc/library/pyclbr.rst:61: WARNING: py:class reference target not found: Function
Doc/library/pyclbr.rst:111: WARNING: py:class reference target not found: Class
Doc/library/pyclbr.rst:152: WARNING: py:class reference target not found: Class
Doc/library/pyclbr.rst:152: WARNING: py:class reference target not found: Class
Doc/whatsnew/3.10.rst:1318: WARNING: py:func reference target not found: pyclbr.readline
Doc/whatsnew/3.10.rst:1318: WARNING: py:func reference target not found: pyclbr.readline_ex

First four fixed by adding the ..class: targets.

@AlexWaygood I think you're going to ask me to also add ! to these Function and Class refs because they appear inside the actual classes?

The last two look like typos (added in #24348) for readmodule and readmodule_ex that are documented and exist in https://github.com/python/cpython/blob/main/Lib/pyclbr.py

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

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📚 Documentation preview 📚: https://cpython-previews--113739.org.readthedocs.build/

[AlexWaygood]

@AlexWaygood I think you're going to ask me to also add ! to these Function and Class refs because they appear inside the actual classes?

Yes please! :D

[AlexWaygood]

A couple more cleanups we could do along the way:

[miss-islington-app]

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

[bedevere-app]

GH-113748 is a backport of this pull request to the 3.12 branch.

[bedevere-app]

GH-113749 is a backport of this pull request to the 3.11 branch.