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