* lisp/net/eudc-capf.el: New file.
* lisp/gnus/message.el (message-mode): Add `eudc-capf-complete' to
`completion-at-point-functions' when a `message-mode' buffer is
created.
* doc/misc/eudc.texi (Inline Query Expansion): Add a new subsection,
describing the new `completion-at-point' mechanism in `message-mode'.
* etc/NEWS (EUDC): Describe the new `completion-at-point' method.