gistfile1.el

(defun git-commit-insert-header (type name email &optional note)
  (let* ((signoff-at (git-commit-find-pseudo-header-position))
         (prev-line  (progn
                       (save-excursion
                         (goto-char (- signoff-at 1))
                         (thing-at-point 'line))))
         (pre        (if (or (string-match "^[^\s:]+:.+$" prev-line)
                             (string-match "\\`\s*$" prev-line))
                         "" "\n"))
         (org (pointer)))

    (goto-char signoff-at)
    (insert (format "%s%s: %s <%s>\n" pre type name email))

    (when note
      (insert (format "[%s: ]\n" email))
      (backward-char 2)
      (when (stringp note) (insert note) (goto-char org)))