Fix trailing whitespace in .cpp, .h, and .idl files (ex. Source/core)

Source/modules/notifications/NotificationClient.h

Index: Source/modules/notifications/NotificationClient.h
diff --git a/Source/modules/notifications/NotificationClient.h b/Source/modules/notifications/NotificationClient.h
index 3fd2dcadd935d55a517ce6887805959824d9f247..8e21247633af361f79999e6d2f79d41380ce0d41 100644
--- a/Source/modules/notifications/NotificationClient.h
+++ b/Source/modules/notifications/NotificationClient.h
@@ -62,7 +62,7 @@ public:
     // When the user closes a page, or quits the client application, all of the page's
     // associated notifications are cleared.
     virtual void clearNotifications(ScriptExecutionContext*) { }
-    
+
     // Informs the presenter that a Notification object has been destroyed
     // (such as by a page transition). The presenter may continue showing
     // the notification, but must not attempt to call the event handlers.