update eventsub docs

Author: IAmTomahawkx

docs/changelog.rst

@@ -23,6 +23,8 @@ Master
         - Fix auto reconnect of websocket. Created tasks by asyncio.create_task() need to be referred to prevent task disappearing (garbage collection).
 
 - ext.eventsub
+    - Documentation
+        - Updated quickstart example to reflect proper usage of callback
     - Additions
         - Updated docs regarding new HypeTrain contribution method ``other`` for :attr:`~twitchio.ext.eventsub.HypeTrainContributor.type`
         - Added Shield Status events

docs/exts/eventsub.rst

@@ -11,7 +11,7 @@ Twitch will send you an HTTP request containing information on the event. This e
 integrating seamlessly into the twitchio Client event dispatching system.
 
 .. warning::
-    This ext requires you to have a public facing ip, and to be able to receive inbound requests.
+    This ext requires you to have a public facing ip AND domain, and to be able to receive inbound requests.
 
 .. note::
     Twitch requires EventSub targets to have TLS/SSL enabled (https). TwitchIO does not support this, as such you should
@@ -26,7 +26,7 @@ A Quick Example
     import twitchio
     from twitchio.ext import eventsub, commands
     bot = commands.Bot(token="...")
-    eventsub_client = eventsub.EventSubClient(bot, "some_secret_string", "/callback")
+    eventsub_client = eventsub.EventSubClient(bot, "some_secret_string", "https://your-url.here/callback")
     # when subscribing (you can only await inside coroutines)
 
     await eventsub_client.subscribe_channel_subscriptions(channel_ID)