LibWeb: Implement [SameObject] behavior for HTMLTableRowElement.cells

Author: https://github.com/awesomekling
Commit: 7d8ff0c581
Pull-request: https://github.com/SerenityOS/serenity/pull/16175
Reviewed-by: https://github.com/ADKaster

Userland/Libraries/LibWeb/HTML/HTMLTableRowElement.h

@@ -25,6 +25,10 @@ public:
 
 private:
     HTMLTableRowElement(DOM::Document&, DOM::QualifiedName);
+
+    virtual void visit_edges(Cell::Visitor&) override;
+
+    JS::GCPtr<DOM::HTMLCollection> mutable m_cells;
 };
 
 }