Add documentation for static var in GDScript reference.

Your Godot version:
4.1.1

Issue description:
As described in https://godotengine.org/article/godot-4-1-is-here/#gdscript, since version 4.1, it is possible to use the static keyword with variable declarations.

The GDScript reference in documentation page still does not account for this and in "keywords" section states:

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

Additionaly I believe that the page should have additional (sub)section with a desription of the static member veriables, like it already has for static functions.

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

[AThousandShips]

This has been fixed, it just hasn't been cherry picked to 4.1 yet, see the current documentation:

Defines a static function or a static member variable.

This was fixed in #7524

Great! I'm closing this accordingly.

[AThousandShips]

Please always check the latest version before opening an issue in the future, if it isn't specific to an older version, and look for other issues (this was already tracked in #7487)

Thank you, I will do that.