Make rebase --autosquash work without --interactive, but limit
rebase.autoSquash's effects to interactive mode, and improve testing
and documentation.

Changes from v3:
- Separate commits for rebase.autoSquash, --autosquash and testing.
- Go back to interpreting rebase.autoSquash as a boolean, but document
  it as only affecting interactive mode.
- In the --autosquash documentation, bring back partial matching as a
  fallback and show what todo list command each squash marker
  corresponds to.

Thanks very much to Junio and Phillip for their reviews. I made plenty
of use of non-interactive autosquash in preparing this version. :)

Andy Koppe (4):
  rebase: fully ignore rebase.autoSquash without -i
  rebase: support --autosquash without -i
  rebase: test autosquash with and without -i
  rebase: rewrite --(no-)autosquash documentation

 Documentation/config/rebase.txt        |  4 ++-
 Documentation/git-rebase.txt           | 34 +++++++++++++----------
 builtin/rebase.c                       | 17 +++++-------
 t/t3415-rebase-autosquash.sh           | 38 +++++++++++++++++++-------
 t/t3422-rebase-incompatible-options.sh | 12 --------
 5 files changed, 58 insertions(+), 47 deletions(-)

-- 
2.43.0-rc1