Update style guide (#8038)

Used get instead of set.

tutorials/scripting/gdscript/gdscript_styleguide.rst

@@ -43,7 +43,7 @@ Here is a complete class example based on these guidelines:
         set = set_is_active
 
     @onready var _state = initial_state:
-        get = set_state
+        set = set_state
     @onready var _state_name = _state.name