Merge branch 'nd/grep-reflog'

Teach the commands from the "log" family the "--grep-reflog" option to limit output by string that appears in the reflog entry when the "--walk-reflogs" option is in effect. * nd/grep-reflog: revision: make --grep search in notes too if shown log --grep-reflog: reject the option without -g revision: add --grep-reflog to filter commits by reflog messages grep: prepare for new header field filter