Userland: Add horizontal mouse scroll support

Author: https://github.com/can3p
Commit: 1662213737
Pull-request: https://github.com/SerenityOS/serenity/pull/11246
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Userland/Demos/Mandelbrot/Mandelbrot.cpp

@@ -350,7 +350,7 @@ void Mandelbrot::mouseup_event(GUI::MouseEvent& event)
 
 void Mandelbrot::mousewheel_event(GUI::MouseEvent& event)
 {
-    zoom(event.wheel_delta() < 0 ? Zoom::In : Zoom::Out, event.position());
+    zoom(event.wheel_delta_y() < 0 ? Zoom::In : Zoom::Out, event.position());
 }
 
 void Mandelbrot::resize_event(GUI::ResizeEvent& event)