LibWeb: Make HTMLCollection and subclasses GC-allocated

Author: https://github.com/awesomekling
Commit: 2bba97964b
Pull-request: https://github.com/SerenityOS/serenity/pull/14816
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/HTML/HTMLTableRowElement.h

@@ -16,7 +16,7 @@ class HTMLTableRowElement final : public HTMLElement {
 public:
     virtual ~HTMLTableRowElement() override;
 
-    NonnullRefPtr<DOM::HTMLCollection> cells() const;
+    JS::NonnullGCPtr<DOM::HTMLCollection> cells() const;
 
     int row_index() const;
     int section_row_index() const;