debian: add line to clean-docs target to delete additional docs file

amend: use context manager for locks (issue5887)

evolve: point to '--abort' in verbose status message f6979d64b9fb (evolve: point to '--abort' in error message, 2018-04-22) changed "hg update -C ." to "hg evolve --abort" in error messages. This commit makes the same change in the verbose status message (the one that warns about unfinished evolve). There's still one mention "hg update -C" in our codebase. That's after "hg evolve --content-divergent" fails, but I don't think "hg evolve --abort" works in that case (yet?).

evolvecmd: add comments and new lines in content-divergence handling logic I have visited this logic three times in last 10 days and I have to re-read the whole code to make sure I don't miss any part. Adding comments will help understanding the code in better and fast way.

evolve: show cset hash in "merging conetnt-divergent changeset" While I was here I also mae de it repo.ui.status() instead of repo.ui.note() to align the behavior with rest of the messages.

evolve: show cset hash in "update to local conflict" message

evolve: use hg.updaterepo() instead of hg.update() to hide stats

evolve: fix the conflicts error message during content-divergence resolution Before last patch, we didn't had an automated way to continue an interrupted content-divergence resolution and we used to show a very long error message on how to continue manually. This patch replaces that long error message with nice small message which tells how to continue and how to abort. We still show `hg update -C .` to abort as we need to test and make `--abort` work in case of content-divergence.

evolve: add logic to continue interrupted content-divergence resolution We continue the interrupted content-divergence using the logic to complete content-divergence which we refactored in it's own function few patches ago. We had to delete evolvestate file before using cmdutil.amend() because otherwise we can't use the function. This leads to a hack which deletes the evolvestate file, we may want to not to use the high level API function here. Also we had to pass evolvestate also to _completecontentdivergent function because of this. This patch also, adds a test which demonstrates that the logic works fine.

evolve: store the evolvestate file when encountering conflicts This patch makes `hg evolve` store the evolvestate file when it encounters merge conflicts while resolving content-divergence.

evolve: take out logic to complete phase-divergence in separate fn This patch takes out the logic to complete the content-divergence resolution to it's own separate function so that we can reuse it in case of interrupted resolution.

evolve: store divergent nodes in evolvestate when resolving content-divergence We need to store the divergent nodes in evolvestate so that we can continue an interrupted phase divergence resolution.

branching: merge stable into default

tests: add test showing `hg evolve --stop` works fine with phase-divergence This patch adds a new test file which contains test demonstrating that `--stop` flag works well while resolving phase-divergence using `hg evolve`.