Emit the notes attached to the commit in "format-patch --notes"
output after three-dashes.
* jc/prettier-pretty-note:
format-patch: add a blank line between notes and diffstat
Doc User-Manual: Patch cover letter, three dashes, and --notes
Doc format-patch: clarify --notes use case
Doc notes: Include the format-patch --notes option
Doc SubmittingPatches: Mention --notes option after "cover letter"
Documentation: decribe format-patch --notes
format-patch --notes: show notes after three-dashes
format-patch: append --signature after notes
pretty_print_commit(): do not append notes message
pretty: prepare notes message at a centralized place
format_note(): simplify API
pretty: remove reencode_commit_message()