Historically, the diff machinery for rename detection had a
hardcoded limit of 32k paths; this is being lifted to allow users
trade cycles with a (possibly) easier to read result.

* en/rename-progress:
  diffcore-rename: make diff-tree -l0 mean -l<large>
  sequencer: show rename progress during cherry picks
  diff: remove silent clamp of renameLimit
  progress: fix progress meters when dealing with lots of work
  sequencer: warn when internal merge may be suboptimal due to renameLimit