revlog: rename constants (API) Feature flag constants don't need "NG" in the name because they will presumably apply to non-"NG" version revlogs. All feature flag constants should also share a similar naming convention to identify them as such. And, "RevlogNG" isn't a great internal name since it isn't obvious it maps to version 1 revlogs. Plus, "NG" (next generation) is only a good name as long as it is the latest version. Since we're talking about version 2, now is as good a time as any to move on from that naming.

localrepo: reformat set literals Putting multiple elements on the same line makes diffs harder to read. Switch to one line per element so future changes are easier on the eyes.

rebase: make sure merge state is cleaned up for no-op rebases (issue5494) If a rebase ends up doing a no-op commit, make sure the merge state is still cleaned up.