Update channel.bits.use docs

Author: chillymosh

twitchio/eventsub/subscriptions.py

@@ -427,6 +427,7 @@ class ChannelBitsUseSubscription(SubscriptionPayload):
     - Cheers in a channel
     - Uses a Power-up
         - Will not emit when a streamer uses a Power-up for free in their own channel.
+    - Sends Combos
 
     .. important::
         Requires a user access token that includes the ``bits:read`` scope. This must be the broadcaster's token.