diff: diff_aligned_abbrev: remove ellipsis after abbreviated SHA-1 value

diff: diff_aligned_abbrev: remove ellipsis after abbreviated SHA-1 value

Neither Git nor the user are in need of this (visual) aid anymore, but
we must offer a transition period.

A follow-up patch (series) will rectify the situation by covering the
new output format as well as the backward compatible one.

Also, fix a typo: "abbbreviated" ---> "abbreviated".

Signed-off-by: Ann T Ropea <bedhanger@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>