Fix background task examples

examples/background_task.py

@@ -9,6 +9,7 @@ class MyClient(discord.Client):
         # an attribute we can access from our task
         self.counter = 0
 
+    async def setup_hook(self) -> None:
         # start the task to run in the background
         self.my_background_task.start()
 

examples/background_task_asyncio.py

@@ -5,6 +5,7 @@ class MyClient(discord.Client):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
+    async def setup_hook(self) -> None:
         # create the background task and run it in the background
         self.bg_task = self.loop.create_task(self.my_background_task())