docs: update web-socket-url example (#3678)

Author: snitin315

examples/web-socket-url/README.md

@@ -6,8 +6,9 @@
 module.exports = {
   // ...
   devServer: {
+    host: "0.0.0.0",
     client: {
-      webSocketURL: "ws://localhost:8080",
+      webSocketURL: "ws://<insert-host>:8080",
     },
   },
 };
@@ -16,9 +17,16 @@ module.exports = {
 Usage via CLI:
 
 ```console
-npx webpack serve
+npx webpack serve --open --host 0.0.0.0 --client-web-socket-url ws://<insert-host>:8080
 ```
 
+_NOTE: replace `<insert-host>` with your local IP Address._
+
+In order to make the server publicly accessible the client needs to know with
+what host to connect to the server. If `--host 0.0.0.0` is given, the client
+would try to connect to `0.0.0.0`. With the `--client-web-socket-url` and related options it is possible to
+override this.
+
 You're now able to explicitly define the protocol used with the `client.webSocketURL` option
 (have a look at the config provided in `webpack.config.js`).