Fix Fort Ludios room type

... and add an impossible when lua tries to create unknown room type.

dat/knox.lua

@@ -65,7 +65,7 @@ function treasure_spot(x,y)
    end
 end
 
-des.region({ region={21,08,35,11}, lit=1, type="orginary" })
+des.region({ region={21,08,35,11}, lit=1, type="ordinary" })
 local treasury = selection.area(21,08,35,11);
 treasury:iterate(treasure_spot);
 

src/sp_lev.c

@@ -3496,6 +3496,8 @@ int defval;
                 res = room_types[i].type;
                 break;
             }
+        if (!room_types[i].name)
+            impossible("Unknown room type '%s'", roomstr);
     }
     Free(roomstr);
     return res;