Sync object event gfx constants

data/maps/OneIsland/map.json

@@ -27,7 +27,7 @@
   ],
   "object_events": [
     {
-      "graphics_id": "OBJECT_EVENT_GFX_BILL",
+      "graphics_id": "OBJ_EVENT_GFX_BILL",
       "x": 12,
       "y": 16,
       "elevation": 3,
@@ -40,7 +40,7 @@
       "flag": "FLAG_HIDE_ONE_ISLAND_BILL"
     },
     {
-      "graphics_id": "OBJECT_EVENT_GFX_OLD_MAN_1",
+      "graphics_id": "OBJ_EVENT_GFX_OLD_MAN_1",
       "x": 16,
       "y": 12,
       "elevation": 3,
@@ -53,7 +53,7 @@
       "flag": "0"
     },
     {
-      "graphics_id": "OBJECT_EVENT_GFX_BALDING_MAN",
+      "graphics_id": "OBJ_EVENT_GFX_BALDING_MAN",
       "x": 13,
       "y": 9,
       "elevation": 3,