Member

Creating this PR as follow-up for #3853 so that we don't have to go back to look for things to remove once API 6.9 drops.
To be merged only one the next API release.

• Added .. versionadded:: NEXT.VERSION, .. versionchanged:: NEXT.VERSION or .. deprecated:: NEXT.VERSION to the docstrings for user facing changes (for methods/class descriptions, arguments and attributes)
• Created new or adapted existing unit tests
• Documented code changes according to the CSI standard <https://standards.mousepawmedia.com/en/stable/csi.html>__
• Added myself alphabetically to AUTHORS.rst (optional)
• Added new classes & modules to the docs and all suitable __all__ s
• Checked the Stability Policy <https://docs.python-telegram-bot.org/stability_policy.html>_ in case of deprecations or changes to documented behavior
• Merge API 6.9 #3898