Check-list for PRs

• Added .. versionadded:: NEXT.VERSION, .. versionchanged:: NEXT.VERSION, .. deprecated:: NEXT.VERSION or ``.. versionremoved:: 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
• [ ] Added myself alphabetically to AUTHORS.rst (optional)
• Added new classes & modules to the docs and all suitable __all__ s
• Checked the Stability Policy in case of deprecations or changes to documented behavior

If the PR contains API changes (otherwise, you can ignore this passage)

• Checked the Bot API specific sections of the Stability Policy

• [ ] Created a PR to remove functionality deprecated in the previous Bot API release (see here)

• New Classes

  • Added self._id_attrs and corresponding documentation
  • __init__ accepts api_kwargs as keyword-only

• Added New Shortcuts

• If Relevant

  • Added new constants at telegram.constants and shortcuts to them as class variables → min & max constants for 1-3 rgeb colors seemed overkill for me … I can add if it's important to anyonen :)
  • Linked new and existing constants in docstrings instead of hard-coded numbers and strings

- [ ] Added new message types to `telegram.Message.effective_attachment`
- [ ] Added new handlers for new update types
    - [ ] Added the handlers to the warning loop in the [`telegram.ext.ConversationHandler`](https://python-telegram-bot.readthedocs.io/en/stable/telegram.ext.conversationhandler.html)
- [ ] Added new filters for new message (sub)types
- [ ] Added or updated documentation for the changed class(es) and/or method(s)
- [ ] Added the new method(s) to `_extbot.py`
- [ ] Added or updated `bot_methods.rst`
- [ ] Updated the Bot API version number in all places: `README.rst` (including the badge) and `telegram.constants.BOT_API_VERSION_INFO`
- [ ] Added logic for arbitrary callback data in `telegram.ext.ExtBot` for new methods that either accept a `reply_markup` in some form or have a return type that is/contains [`telegram.Message`](https://python-telegram-bot.readthedocs.io/en/stable/telegram.message.html)