LibGUI: Fix a typo

Author: https://github.com/cammo1123
Commit: 4e3b965d7f
Pull-request: https://github.com/SerenityOS/serenity/pull/16321
Reviewed-by: https://github.com/nico ✅

Userland/Libraries/LibGUI/Widget.h

@@ -373,7 +373,7 @@ protected:
     // This is called after children have been painted.
     virtual void second_paint_event(PaintEvent&);
 
-    virtual void layout_relevant_change_occured();
+    virtual void layout_relevant_change_occurred();
     virtual void custom_layout() { }
     virtual void did_change_font() { }
     virtual void did_layout() { }