evolve: add a help topic `Interrupted-Evolve` This help topic contains description on how the various flags work during interrupted evolve. This help topic will be included in error message during interrupted evolve in next patch.

branching: merge with stable

changelog: fix version number error

evolve: return the new node formed only as the replacement sometimes, the the other content divergent changeset is obsoleted in favour of the local divergent changeset in which case we should not store that as a replacement because `hg evolve --abort` will strip that changeset. Let's make sure we return the newnode only if formed. The test results shows that we are still not 100% accurate as we need to strip an obsmarker.

tests: add more test of --abort flag for content-divergence resolution This patch adds test when we resolve multiple content-divergence changesets at once and resolution fo first content-divergence does not form new commits, resolution of second one leads to conflicts. As the output shows, we are wrongly stripping a changeset here, which should be fixed in next patch.

evolve: prompt user for branch selection while resolving content-divergence When resolving content-divergence, there can be case when both the content-divergent changesets are on different named branches. In that case, we are not sure which branch should the resolution commit should be on. This patch adds logic to prompt user to choose the branch which the resolution commit should be on and then creates the new resolution commit on that branch. This also adds a new test file which have tests for the branch selection feature we have added.