growth feedback

Fido grows up into a large dog.
     The soldier becomes a sargeant.

Similar feedback was previously given only when the monster was going to be
killed off due to its new form having been genocided.

doc/fixes34.4

@@ -297,6 +297,7 @@ support ^R (and ^L in numpad mode) to request display repaint during direction
 	choosing and location choosing prompting modes
 intelligent pets will use keys to unlock doors
 destroyed drawbridge leaves some iron chains
+give feedback when a nearby monster grows into a stronger form
 
 
 Platform- and/or Interface-Specific New Features

src/makemon.c

@@ -1507,6 +1507,10 @@ struct monst *mtmp, *victim;
 		set_mon_data(mtmp, ptr, -1);	/* keep mvitals[] accurate */
 		mondied(mtmp);
 		return (struct permonst *)0;
+	    } else if (canspotmon(mtmp)) {
+		pline("%s %s %s.", Monnam(mtmp),
+		      humanoid(ptr) ? "becomes" : "grows up into",
+		      an(ptr->mname));
 	    }
 	    set_mon_data(mtmp, ptr, 1);		/* preserve intrinsics */
 	    newsym(mtmp->mx, mtmp->my);		/* color may change */