[PATCH] Fix systemd socket-unit example

[Ulrich Ölmann]

* doc/emacs/misc.texi (Emacs Server): The socket containing directory
is per default created with permissions 0755 by the socket-unit.
However this is considered unsafe since commit [1], so enhance unit
example with systemd configuration directive `DirectoryMode=' to
create it with safe permissions, see
https://www.freedesktop.org/software/systemd/man/systemd.socket.html#DirectoryMode=

[1] 2003-04-12 "(server-socket-name): Use new safe location for socket."
---
It took me some hours to track the problem down as `emacs --daemon'
did not complain about what it misliked and only refused to cooperate
with `emacsclient'. Unfortunately I am only a emacs user and no
developer so I do not know how to enhance that situation.

 doc/emacs/misc.texi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 4865ee175180..327ae3e31e30 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -1709,6 +1709,7 @@ Emacs Server
 @example
 [Socket]
 ListenStream=/path/to/.emacs.socket
+DirectoryMode=0700
 
 [Install]
 WantedBy=sockets.target
-- 
2.29.2