LibWeb: Use the spec-mandated change-attribute when setting an attribute

Author: https://github.com/trflynn89
Commit: 2d97dd019e
Pull-request: https://github.com/SerenityOS/serenity/pull/20912
Reviewed-by: https://github.com/ADKaster ✅

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -158,7 +158,7 @@ WebIDL::ExceptionOr<void> Element::set_attribute(DeprecatedFlyString const& name
     // 5. Change attribute to value.
     else {
         old_value = attribute->value();
-        attribute->set_value(value);
+        attribute->change_attribute(value);
     }
 
     attribute_changed(attribute->local_name(), value);