LibWeb: Implement HTMLTableSectionElement::insertRow()

Author: https://github.com/IdanHo
Commit: 009588eb28
Pull-request: https://github.com/SerenityOS/serenity/pull/13014
Reviewed-by: https://github.com/awesomekling ✅

Userland/Libraries/LibWeb/HTML/HTMLTableSectionElement.h

@@ -19,6 +19,7 @@ public:
     virtual ~HTMLTableSectionElement() override;
 
     NonnullRefPtr<DOM::HTMLCollection> rows() const;
+    DOM::ExceptionOr<NonnullRefPtr<HTMLTableRowElement>> insert_row(long index);
 };
 
 }