ST. LOUIS — Acquiring Pavel Buchnevich was one of the strongest additions Blues general manager Doug Armstrong has made during his tenure here. Buchenvich is an excellent all-around winger. He plays on the top forward line with Robert Thomas and Jordan Kyrou at even strength and on the top power-play unit. He demands much of himself, which has caused him to press at times this season. But overall, he has scored at a point-per-game pace since joining the Blues. He also kills penalties. He checks opponents with an edge. He adds to the team’s chemistry with his unique personality. It’s no wonder …