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/fountain.c

@@ -259,7 +259,7 @@ drinkfountain(void)
         for (ii = 0; ii < A_MAX; ii++)
             if (ABASE(ii) < AMAX(ii)) {
                 ABASE(ii) = AMAX(ii);
-                gc.context.botl = 1;
+                display.botl = 1;
             }
         /* gain ability, blessed if "natural" luck is high */
         i = rn2(A_MAX); /* start at a random attribute */