Add _set_cog to Command

Author: HexF

discord/ext/commands/core.py

@@ -1144,6 +1144,9 @@ async def can_run(self, ctx: Context) -> bool:
         finally:
             ctx.command = original
 
+    def _set_cog(self, cog):
+        self.cog = cog
+
 class GroupMixin(Generic[CogT]):
     """A mixin that implements common functionality for classes that behave
     similar to :class:`.Group` and are allowed to register commands.