Added Missing Optional Parameter Documentation

Added the missing optional parameter `stack name` to `notifyWithDefaults` method documentation

Author: MhdSyrwan

README.md

@@ -107,7 +107,7 @@ Display a generic PNotify notification with the options you pass to it. It ignor
 Same as `notify` but will merge the options with defaults. Useful when you only want to override or add one options, without 
 clearing all defaults.
 
-`notificationService.notifyWithDefaults(options);`
+`notificationService.notifyWithDefaults(options, [stack name]);`
 
 ### Provider
 
@@ -242,4 +242,4 @@ To the [angular-pines-notify](https://github.com/mykabam/angular-pines-notify) c
 - [mibamur](https://github.com/mibamur)
 - [MaximilianoRicoTabo](https://github.com/MaximilianoRicoTabo)
 
-Thanks to [mehdi-ghezal](https://github.com/mehdi-ghezal) for stack implementation.
+Thanks to [mehdi-ghezal](https://github.com/mehdi-ghezal) for stack implementation.