Expand description of start-server.

tmux.1

@@ -1287,6 +1287,17 @@ shows the parsed commands and line numbers if possible.
 Start the
 .Nm
 server, if not already running, without creating any sessions.
+.Pp
+Note that as by default the
+.Nm
+server will exit with no sessions, this is only useful if a session is created in
+.Pa ~/.tmux.conf ,
+.Ic exit-empty
+is turned off, or another command is run as part of the same command sequence.
+For example:
+.Bd -literal -offset indent
+$ tmux start \\; show -g
+.Ed
 .It Xo Ic suspend-client
 .Op Fl t Ar target-client
 .Xc