evolve: remove revset calls in warnobserror revset have serious performance impact in several case. The resulting code is a bit too complicated to my taste. I hope for much simpler implementation in core anyway.

evolve: drop "troubles" and "troubled" method now in core

test: drop rebase test We assume that the mercurial rebases tests suite is strong enough now.

doc: fix grammar, spelling, punctuation I restrained myself to making only changes that turn bad English into good English. There are still opportunities to improve, but other changes require some discussion and review. This change should be uncontroversial.