docs: Update README.md and add image for CodeXP Notification

Author: ByteAurora

README.md

@@ -72,9 +72,13 @@ Completed challenges are added under the "Completed Challenges" section. Also, m
 <br>
 
 ## Notification
-Whenever a challenge is completed or a level up occurs, a notification is provided to inform you of the details.
+Whenever a challenge is completed or a level up occurs, a notification is provided to inform you of the details. You can choose to display the notification as an IntelliJ notification or a CodeXP notification.
 
-![Notification](https://github.com/ILoveGameCoding/intellij-codexp/blob/main/images/notification.jpg)
+#### IntelliJ Notification
+![IntelliJ Notification](https://github.com/ILoveGameCoding/intellij-codexp/blob/main/images/intellij_notification.jpg)
+
+#### CodeXP Notification
+![CodeXP Notification](https://github.com/ILoveGameCoding/intellij-codexp/blob/main/images/codexp_notification.png)
 
 ---
 Plugin based on the [IntelliJ Platform Plugin Template][template].