comment a tiny unimportant pathfinding-cost error about ZoC at destination

(a bit sensible to change, it's possible that AI rely on it)

src/pathfind.cpp

@@ -329,6 +329,10 @@ double shortest_path_calculator::cost(const gamemap::location& /*src*/,const gam
 	// since we sacrifice this turn's movement. Take that into account here.
 	int additional_cost = base_cost > remaining_movement ? remaining_movement : 0;
 
+	// The isDist check is obsolete and introduce a little inaccurancy.
+	// It comes trom the time when we returned getNoPathValue() in ZoC
+	// But pathfinding calls with a small maximum path length
+	// (like some AI stuff do) maybe rely on this.
 	if (!isDst && enemy_zoc(map_,units_,teams_, loc, viewing_team_, unit_.side())
 			&& !unit_.get_ability_bool("skirmisher", loc)) {
 		// Should cost us remaining movement.