@SUccess (object) [=(message)]
Sets the success message for (object).
If no (message) is specified it erases any previously set (message).
Success messages have similar purposes on different types of objects:
ON ROOMS: It's appended to the room desc when the player enters or looks.
ON THINGS: It's displayed to the player that picks it up.
ON GROUPS: It's displayed to the player that just became a member.
ON EXITS: It's displayed to the player that used it successfully.
*new* If omitted, a "You (exitname)" will appear for "command exits."
ON PLAYERS: It's sent to the player that just paged you successfully.
*new* It's an Auto-Reply for whatever use you may have.