Deprecate 'activate-with-no-open-windows' event.

atom/browser/mac/atom_application_delegate.mm

@@ -56,6 +56,7 @@
   if (flag) {
     return YES;
   } else {
+    // Deprecated API, for compatibility.
     browser->ActivateWithNoOpenWindows();
     return NO;
   }

docs/api/app.md

@@ -94,12 +94,6 @@ must be registered to be opened by your application.
 
 You should call `event.preventDefault()` if you want to handle this event.
 
-### Event: 'activate-with-no-open-windows' _OS X_
-
-Emitted when the application is activated while there are no open windows, which
-usually happens when the user has closed all of the application's windows and
-then clicks on the application's dock icon.
-
 ### Event: 'activate' _OS X_
 
 Returns: