Merge JoinMarket-Org/joinmarket-clientserver#1455: docs: add restart config to directory node service

cb2ad2b845 docs: add restart config to directory node service (openoms)

Pull request description:

  Found it while testing that if Tor fails the start-dn.py exits and by default systemd does not restart it.

  This small recommended change ensures that the process is restarted both in case of graceful and ungraceful exit and leaves 10 seconds between.

ACKs for top commit:
  kristapsk:
    utACK cb2ad2b845. Should not hurt in any way. Merging.

Tree-SHA512: d916553e091125a765b27a6c9a5bbb11b9a653d37af8e74e9521285a55ee91bf54f4a8c47bb4136762c6321036983c2921880db9c5e3ce4dbc0704d9a7414e13

docs/onion-message-channels.md

@@ -190,6 +190,8 @@ After=network-online.target
 Type=simple
 ExecStart=/bin/bash -c 'cd /path/to/joinmarket-clientserver && source jmvenv/bin/activate && cd scripts && python start-dn.py 'Greetings from Directory Node' --datadir=/path/to/chosen/datadir'
 User=user
+Restart=always
+RestartSec=10
 
 [Install]
 WantedBy=multi-user.target