LibWeb/DOM: Add document getter to AbstractElement

Author: https://github.com/AtkinsSJ
Commit: 9bc5c6fb35
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5400
Reviewed-by: https://github.com/tcl3 ✅

Libraries/LibWeb/DOM/AbstractElement.cpp

@@ -21,6 +21,11 @@ void AbstractElement::visit(GC::Cell::Visitor& visitor) const
     visitor.visit(m_element);
 }
 
+Document& AbstractElement::document() const
+{
+    return m_element->document();
+}
+
 GC::Ptr<Layout::NodeWithStyle> AbstractElement::layout_node()
 {
     if (m_pseudo_element.has_value())