Deprecated `Color8` is still mentioned

[notroid5]

Your Godot version:
4.5.stable

Issue description:
Color8 is deprecated but still mentioned a few times.
(Not sure if it should be changed in the C# docs as well, will wait for feedback in the PR.)

URL to the documentation page:
https://docs.godotengine.org/en/latest/classes/class_color.html
https://docs.godotengine.org/en/latest/tutorials/scripting/c_sharp/c_sharp_differences.html
https://docs.godotengine.org/en/latest/tutorials/plugins/editor/import_plugins.html