A function added by the Fallout Script Extender.
Adds the calling reference at the given index (or at the end if not provided)
(int) ref.ListAddReference form list:ref
(int) ref.ListAddRef form list:ref
Note that forms added to a list with this function will not persist across savegames. If you need to add items to a list that will be preserved in a saved game, use AddFormToFormList