This is, by all reasonable measures, a high-water mark for an evolving Washington Capitals team that is not even a fifth of the way through its season. The Caps just shut out the reigning Stanley Cup champion Vegas Golden Knights. They are on a 7-1-1 heater. They sit in second place in the Metropolitan Division. They aren’t at full strength, and their power play is a mess. Yet they’re banking points under a first-year coach.