Merge pull request #302 from ToxicKidz/fix/checks

Change `commands.check` to allow `ApplicationCommand`

discord/ext/commands/core.py

@@ -1723,7 +1723,7 @@ async def only_me(ctx):
     """
 
     def decorator(func: Union[Command, CoroFunc]) -> Union[Command, CoroFunc]:
-        if isinstance(func, Command):
+        if isinstance(func, _BaseCommand):
             func.checks.append(predicate)
         else:
             if not hasattr(func, '__commands_checks__'):