Make `SEARCH` work

[bobbylight]

Make the SEARCH menu option actually work:

• Treasure chests give the message: "{hero} searched the ground all about.\nThere is a treasure box." Note this does not open the treasure chest in this game (that's the purpose of TAKE).
• Hidden items (such as the flute or Erdrick's Token)

This ticket doesn't concern itself with removing the flute or Erdrick's Token from the map. It's just for the SEARCH action to find the data in the map and add the relevant item to the user's inventory.