AnimationTree documentation simplification and expansion

[saabdo42]

Simplified AnimationTree language, added documentation for Advance Expression, made images webp and colorblind friendly with more descriptive names.

Fixes: https://github.com/godotengine/godot-docs/issues/9699 Fixes: https://github.com/godotengine/godot-docs/issues/7753 Fixes: https://github.com/godotengine/godot-docs/issues/7658

[fire]

Is there a good way to preview doc changes?

[fire]

Not familiar with spinx errors.

Warning, treated as error:
/home/runner/work/godot-docs/godot-docs/tutorials/animation/animation_tree.rst:19:Title underline too short.

AnimationTree and AnimationPlayer
-------------------------
make: *** [Makefile:37: dummy] Error 2

[saabdo42]

Ok just fixed that error

[saabdo42]

I'm not sure how to assign issues to pull requests, but this fixes #9699 and #7753

[fire]

Add this to your first post.

Fixes: https://github.com/godotengine/godot-docs/issues/9699
Fixes: https://github.com/godotengine/godot-docs/issues/7753

[skyace65]

This PR needs to be rebased.

[saabdo42]

What does that mean? (sorry lol)

[fire]

Let me know if you have any questions after reading this. https://docs.godotengine.org/en/stable/contributing/workflow/pr_workflow.html

[saabdo42]

Any update on this?

[skyace65]

Still need to review this, apologies for the long wait

[fire]

I'll put a bookmark that someone from the animation team needs to look at this.

[skyace65]

Merging this as is due to the lack of a response from the animation team.

@saabdo42 Thanks! Apologies on how long this took, congrats on your first merged PR!