Support opening a new connection when reverting a telnet buffer

* net/telnet.el (telnet-connect-command): New variable.
(telnet-revert-buffer): New function.
(telnet-mode): Use `telnet-revert-buffer' as `revert-buffer-function'.
(telnet, rsh): Set `telnet-connect-command' accordingly (bug#18312).

Copyright-paperwork-exempt: yes

1 files changed, 5 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index d237e4ccb0f..7de94a7b11d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -475,6 +475,11 @@ current and the previous or the next line, as before.
 
 * Changes in Specialized Modes and Packages in Emacs 27.1
 
+---
+** telnet-mode
+*** Reverting a buffer in `telnet-mode' will restart a closed
+connection.
+
 ** goto-addr
 *** A way to more conveniently specify what URI address schemes that
 should be ignored have been added via the