* mh-comp.el (mh-redist-full-contents) Convert defvar to defcustom.

* mh-comp.el (mh-redist-full-contents) Convert defvar to defcustom.
(mh-smail, mh-extract-rejected-mail, mh-forward, mh-redistribute)
(mh-reply, mh-send, mh-send-other-window)
(mh-fill-paragraph-function): Sync docstrings with manual.

* mh-customize.el (mh-redist-full-contents-flag): Convert defvar to
defcustom.
(mh-compose-forward-as-mime-flag)
(mh-compose-letter-function, mh-forward-subject-format)
(mh-insert-x-mailer-flag, mh-reply-default-reply-to)
(mh-reply-show-message-flag, mh-letter-mode-hook): Sync docstrings
with manual.