Function allow_insert_attribute

Source/ThirdParty/pugixml/pugixml.cpp:3711–3714

	}

	PUGI__FN bool allow_insert_attribute(xml_node_type parent)
	{
		return parent == node_element || parent == node_declaration;
	}

	PUGI__FN bool allow_insert_child(xml_node_type parent, xml_node_type child)
	{