Add the forum_data var to the core.viewforum_get_topic_ids_data event

I have an extension that needs to modify the SQL for a specific forum. To do this, I'm calling the core.viewforum_get_topic_ids_data event from viewforum.php. However, the current available vars do not include arrays that have the forum_id. To address this issue, I'm proposing adding forum_data to the list of available vars. Thank you!