git-gui: Improve directions regarding POT update in po/README
Keeping POT up to date relative to the software is absolutely
necessary. What is unwarranted is updating language files at
the same time by running msgmerge without checking if there is
any outstanding translation work first. If we assume that the
translators do not have access to msgmerge, that is a good service
to them (the less they have to do, the better), but otherwise,
it is better to be leave po/${language}.po files alone.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>