b864: Treasure chests and ST_SPECIALITEM

Okay, collecting a special item from a treasure chest combo (normal, locked, and boss) doesn't update the screen state ST_SCREENITEM. All other ways of collecting special items (ie. item cellar, tall grass with inherent flag 10, etc.) do update it correctly, only the treasure chest combos do not. If you want to see the script I used to find this, it is here (a PureZC forum thread). If you need me to upload a test quest file I can, just let me know.