* lisp/message.el (message-yank-original): If `message-yank-add-new-references'

* lisp/message.el (message-yank-original): If `message-yank-add-new-references'
is non-nil and this command is called interactively, new IDs from the yanked
article will be added to `References' field.
(message-yank-add-new-references): New user option.
(message-header-format-alist): Use `message-shorten-reference' for `References'
in default.
* lisp/gnus-msg.el (gnus-inews-yank-articles): Replace `References' field with
the gathered Message-IDs and References if more than one articles are given.