Perhaps some NNTP clients would be unhappy with the old value
"y". So use a bit more bandwidth+space to use the server-name
and historical "!not-for-mail" tail-entry to better conform to
a published RFC.
Reported-by: Andrey Melnikov <temnota.am@gmail.com>
(cherry picked from commit
47559005ee678592808c351daa1c9f2682beb248)