evolve: use more often seen metavariables in command synopsis strings

Also use ellipsis when multiple options are acceptable.

--HG--
branch : stable
2 jobs for topic/stable/command-synopsis in 10 minutes and 43 seconds (queued for 1 second)
Status Name Job ID Coverage
  Test
passed flake8 #46149

00:00:12

passed tests #46150

00:10:43