Near the end of Mark Morris’s new dance “The,” couples sway happily in each other’s arms before circling the stage, side by side, running, their clasped hands uplifted. On Friday night, this little victory lap felt particularly resonant: Earlier, the Supreme Court had given us much to celebrate, and those sweetly jubilant duos — male-female, male-male, female-female — said so much, as dance often does, without a word.