Add bind address example to websockets

docs/servers/websocket.md

@@ -34,6 +34,9 @@ don't already have it defined).
                         // non-secure ws://
                         port: 8810
                         enabled: true
+
+                        //  optional bind address
+                        address: 127.0.0.1
                     }
                     wss: {
                         //  secure-over-tls wss://