Merge branch 'mf/format-patch-cover-letter-format'

"git format-patch --cover-letter" learns to use a simpler format instead of the traditional shortlog format to list its commits with a new --cover-letter-format option and format.commitListFormat configuration variable. * mf/format-patch-cover-letter-format: docs: add usage for the cover-letter fmt feature format-patch: add commitListFormat config format-patch: add ability to use alt cover format format-patch: move cover letter summary generation pretty.c: add %(count) and %(total) placeholders