Fixes typo, adds missing item_state and new medkit for psychologists.

Amoutn changed to amount ; O2 first-aid kit now has an actual item_state and there is a new medkit: the psychiatry first-aid kit that contains medicine for psychiatrists to give out!

The purple medkit was already an icon_state in code, so I didn't add it, I just made the item_states for it.

TODO: Bother a mapper to get the kit @ psychiatrist office or supply rooms.