When introducing git stash push in f5727e26e4 ("stash: introduce push
verb", 2017-02-19), I forgot to add it to the completion code. Add it
now.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>