Merge branch 'nd/i18n'

Merge branch 'nd/i18n'

More message strings marked for i18n.

By Nguyễn Thái Ngọc Duy (10) and Jonathan Nieder (1)
* nd/i18n:
  help: replace underlining "help -a" headers using hyphens with a blank line
  i18n: bundle: mark strings for translation
  i18n: index-pack: mark strings for translation
  i18n: apply: update say_patch_name to give translators complete sentence
  i18n: apply: mark strings for translation
  i18n: remote: mark strings for translation
  i18n: make warn_dangling_symref() automatically append \n
  i18n: help: mark strings for translation
  i18n: mark relative dates for translation
  strbuf: convenience format functions with \n automatically appended
  Makefile: feed all header files to xgettext