Remove another suicide reference

Was missed in angband/angband#5792 .

src/player-quest.c

@@ -472,7 +472,7 @@ bool quest_monster_death_check(struct player *p, const struct monster *mon)
 		p->upkeep->redraw |= (PR_TITLE);
 		msg("*** CONGRATULATIONS ***");
 		msg("You have won the game!");
-		msg("You may retire (commit suicide) when you are ready.");
+		msg("You may retire (key is shift-q) when you are ready.");
 	}
 
 	return true;