LibJS+LibWeb: Explicitly mark ignored members in visit_edges methods

Author: https://github.com/mattco98
Commit: a9d192e882
Pull-request: https://github.com/SerenityOS/serenity/pull/17979
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/HTML/Scripting/Environments.cpp

@@ -37,6 +37,7 @@ void EnvironmentSettingsObject::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(target_browsing_context);
+    visitor.ignore(m_outstanding_rejected_promises_weak_set);
 }
 
 JS::ExecutionContext& EnvironmentSettingsObject::realm_execution_context()