evolve: Changelog

tests: demonstrate an orphan changeset cause "relocate node on top of itself" See issue6097.

obslog: only indent the first chunk and chunks just after newlines (issue6175)

tests: demonstrate too many spaces in olog -p output with word-diff

rewind: add --keep flag that "doesn't modify working directory" The actual logic is more complicated than the flag description, but it's sufficiently similar to other --keep flags in action. Unlike strip (or prune), rewind always needs to modify the working directory to commit new revisions that "revive" old ones [1], see _revive_revision() (and rewriteutil.rewrite()). Because of that we don't prevent rewind from modifying wdir, but instead use hg.updaterepo() to update to the old changeset after the "revival" process is complete. Then we rebuild the dirstate based on the commit that rewind would update to without --keep. Since dirstate.rebuild() doesn't restore status of some files (added, removed, also copies and renames), we rely on cmdutil.revert(). It's a fairly crude solution and needs to be removed when implementing the missing copy tracing between oldctx and newctx (which are related only by obsolescence). [1] IOW this means that --keep doesn't allow rewinding if wdir is dirty (unlike e.g. strip).

tests: separate rewinding of merge commits, temporarily drop an error case The error case will come back in the following commit, because it organically fits there without the need of a separate working clone.