Don't terminate WebSocket messages with a trailing newline

As per https://electrumx-spesmilo.readthedocs.io/en/latest/protocol-basics.html#message-stream

Author: shesek

contrib/runits/websocket.runit

@@ -1,3 +1,3 @@
 #!/bin/sh -e
 exec 2>&1
-exec /srv/explorer/websocat/bin/websocat -E -b l-ws-unix:/var/electrum-websocket.sock tcp:127.0.0.1:50001
+exec /srv/explorer/websocat/bin/websocat -E --linemode-strip-newlines l-ws-unix:/var/electrum-websocket.sock msg2line:tcp:127.0.0.1:50001