Merge branch 'js/detached-stash'

* js/detached-stash:
  t3903: fix broken test_must_fail calls
  detached-stash: update Documentation
  detached-stash: tests of git stash with stash-like arguments
  detached-stash: simplify git stash show
  detached-stash: simplify git stash branch
  detached-stash: refactor git stash pop implementation
  detached-stash: simplify stash_drop
  detached-stash: simplify stash_apply
  detached-stash: work around git rev-parse failure to detect bad log refs
  detached-stash: introduce parse_flags_and_revs function