EUDC: Support querying all servers

EUDC: Support querying all servers

* lisp/net/eudc.el (eudc-expand-try-all): New command.
(eudc-expand-inline): Add `try-all-servers' optional argument.
Update `eudc-query-with-words' call.
(eudc-query-with-words): Add `try-all-servers' optional argument.
Move response formatting into main query loop.  Query next server
if `try-all-servers' is non-nil.
(eudc-tail-menu): Add "Expand Inline Query Trying All Servers"
menu item.
* doc/misc/eudc.texi (Installation): Recommend
eudc-expand-try-all.
(Emacs-only Configuration): Likewise.
(Inline Query Expansion, Inline Query Expansion): Likewise.
Document `eudc-expand-try-all'.
* etc/NEWS (EUDC): Describe new 'eudc-expand-try-all' command.