added notification overview

docs/content/advanced/backend/subscribers/events-list.md

@@ -1862,4 +1862,4 @@ Object of the following format:
 ## What’s Next 🚀
 
 - Learn how you can [use services in subscribers](create-subscriber.md#using-services-in-subscribers).
-- Learn how to [create notifications](../../../how-to/notification-api.md) in Medusa.
+- Learn how to [create notifications](../notification/overview.md) in Medusa.