Updated display modes doc link

Changed old link to https://superpwa.com/doc/web-app-manifest-display-modes/

Author: arunbasillal

README.MD

@@ -122,7 +122,7 @@ Here are the current features of Super Progressive Web Apps:
 * New in version 1.8: Compatibility issues with OneSignal are now resolved! 
 * New in version 1.8: New Add-On: [Apple Touch Icons](https://superpwa.com/addons/apple-touch-icons/?utm_source=GitHub&utm_medium=Readme-version) that sets your app icons as Apple Touch Icons. 
 * New in version 2.0: SuperPWA is now compatible with WordPress installed in a sub-folder. 
-* New in version 2.0: You can now set [display property](https://superpwa.com/web-app-manifest-display-modes/?utm_source=GitHub&utm_medium=Readme-version) from SuperPWA settings. 
+* New in version 2.0: You can now set [display property](https://superpwa.com/doc/web-app-manifest-display-modes/?utm_source=GitHub&utm_medium=Readme-version) from SuperPWA settings. 
 
 #### 🔮 Upcoming features:
 * Offline Indicator Notice.