docs: Add notification priority 1 information

Author: cbaker6

doc/notification.markdown

@@ -192,6 +192,7 @@ Provide one of the following values:
   * `10` - The push notification is sent to the device immediately. (Default)
     > The push notification must trigger an alert, sound, or badge on the device. It is an error to use this priority for a push notification that contains only the `content-available` key.
   * `5` - The push message is sent at a time that conserves power on the device receiving it.
+  * `1` - The push message is sent at a time to prioritize the device’s power considerations over all other factors for delivery, and prevent awakening the device.
 
 
 #### notification.pushType
@@ -202,4 +203,4 @@ The type of the notification. The value of this header is `alert`, `background`,
 
 The value of this header must accurately reflect the contents of your notification's payload. If there is a mismatch, or if the header is missing on required systems, APNs may delay the delivery of the notification or drop it altogether.
 
-[pl]:https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/CreatingtheNotificationPayload.html "Local and Push Notification Programming Guide: Apple Push Notification Service"
+[pl]:https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/CreatingtheNotificationPayload.html "Local and Push Notification Programming Guide: Apple Push Notification Service"