bundle the display-related hints, that tell bot() and others

that an update is required, into a struct. Remove it from
context since there is no reason to save those.

src/dig.c

@@ -1096,7 +1096,7 @@ use_pick_axe2(struct obj *obj)
         You("hit yourself with %s.", yname(uwep));
         Sprintf(buf, "%s own %s", uhis(), OBJ_NAME(objects[obj->otyp]));
         losehp(Maybe_Half_Phys(dam), buf, KILLED_BY);
-        gc.context.botl = 1;
+        display.botl = 1;
         return ECMD_TIME;
     } else if (u.dz == 0) {
         confdir(FALSE);