* Improve autocompletion for mobject.animate to show Mobject methods
- Added type hint `-> _AnimationBuilder | Self` to `Mobject.animate`, enabling autocompletion for `Mobject` methods after `mobject.animate`.
- Prioritized `typing_extensions.Self` over `typing.Self` in imports, so autocompletion of `Mobject` methods also works in Python < 3.11.
* Support `mobject.animate.` autocompletion in IPython
* Add docstring to `__dir__` and add return type hint
* improve docsting `__dir__` _AnimationBuilder