It's been deprecated since fd2ebf14db (stash: mark "git stash save"
deprecated in the man page, 2017-10-22) and the previous commit removed
further documentation suggesting to use it.
Since we recommend push instead, stop completing for "save" and remove a
special case in completion code. It still appears for "git stash <tab>"
when GIT_COMPLETION_SHOW_ALL=1, and when typed explicitly we still
complete options for
git stash save --<tab>
which is helpful for folks with finger-memory for save.
Signed-off-by: D. Ben Knoble <ben.knoble@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>