State that static variables are supported

[hydroper]

Your Godot version: 4

Issue description: The GDScript reference says that static members are not allowed, but in 4.1 that changed.

static: Defines a static function. Static member variables are not allowed.

URL to the documentation page (if already existing): https://docs.godotengine.org/en/latest/tutorials/scripting/gdscript/gdscript_basics.html

[AThousandShips]

Note that this is the wrong page, it should be latest:
https://docs.godotengine.org/en/latest/tutorials/scripting/gdscript/gdscript_basics.html, on "stable" it's still true