GDScript: Remove function of continue for match statement

The keyword is confusing and rarely is used in the intended way. It is
removed now in favor of a future feature (pattern guards) to avoid
breaking compatibility later.

modules/gdscript/tests/scripts/parser/features/match.gd

@@ -3,8 +3,6 @@ func test():
 	match i:
 		"Hello":
 			print("hello")
-			# This will fall through to the default case below.
-			continue
 		"Good bye":
 			print("bye")
 		_: