Merge branch 'jc/stash-pop-not-popped'

"stash pop", upon failing to apply the stash, refrains from
discarding the stash to avoid information loss.  Be more explicit
in the error message.

The wording may want to get a bit more bikeshedding.

* jc/stash-pop-not-popped:
stash pop: mention we did not drop the stash upon failing to apply

diff --cc git-stash.sh
Simple merge