Fix translator not always being added to a Command

Author: EvieePy

twitchio/ext/commands/core.py

@@ -1502,7 +1502,7 @@ def wrapper(func: Any) -> Any:
         if isinstance(func, Command):
             func._translator = inst
         else:
-            func.__command_translator = inst
+            func.__command_translator__ = inst
 
         return func  # type: ignore