Method append_copy

Source/ThirdParty/pugixml/pugixml.cpp:5009–5017

	}

	PUGI__FN xml_attribute xml_node::append_copy(const xml_attribute& proto)
	{
		if (!proto) return xml_attribute();

		xml_attribute result = append_attribute(proto.name());
		result.set_value(proto.value());

		return result;
	}

	PUGI__FN xml_attribute xml_node::prepend_copy(const xml_attribute& proto)
	{