Switch from low-level loop.create_task and asyncio.ensure_future (#5626)

* Switch from low-level loop.create_task and asyncio.ensure_future

* Patch vendored discord.ext.menus to use modern APIs as well

That ext is no longer maintained by Danny anyway so...

* black

redbot/cogs/admin/announcer.py

@@ -30,7 +30,7 @@ class Announcer:
         """
         if self.active is None:
             self.active = True
-            self.ctx.bot.loop.create_task(self.announcer())
+            asyncio.create_task(self.announcer())
 
     def cancel(self):
         """