update chat quickstart

Author: angellan-msft

articles/communication-services/quickstarts/chat/includes/chat-swift.md

@@ -388,9 +388,9 @@ semaphore.wait()
 ```
 ## Push notifications
 
-Push notifications let clients to be notified for incoming messages in a chat thread in situations where the mobile app is not running in the foreground.
+Push notifications notify clients of incoming messages in a chat thread in situations where the mobile app is not running in the foreground.
 Currently sending chat push notifications with Notification Hub is supported for IOS SDK in version 1.3.0-beta.1.
-Please refer to the article "Enable Push Notification in your chat app" under "Tutorial" section for details.
+Please refer to the article [Enable Push Notification in your chat app](../../../tutorials/add-chat-push-notifications.md) for details.
 
 ## Run the code