fmt-merge-msg: add '--(no-)log' options and 'merge.log' config variable

These are new synonyms to the '--(no-)summary' option and the
'merge.summary' config variable, but are consistent with the soon to be
added 'merge --(no-)log' options.  The 'merge.summary' config variable and
'--(no-)summary' options are still accepted, but are advertised to be
removed in the future.

'merge.log' takes precedence over 'merge.summary' if they are both set
inconsistently.

Update documentation and tests accordingly.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

0 files changed, 0 insertions, 0 deletions