Fix formatting in code snippet (#4600)

* Fix formatting in code snippet

* Update index.html

Author: shamilDzhakeev

files/en-us/web/api/web_workers_api/using_web_workers/index.html

@@ -60,12 +60,12 @@ <h3 id="Sending_messages_to_and_from_a_dedicated_worker">Sending messages to and
 <p>The magic of workers happens via the {{domxref("Worker.postMessage", "postMessage()")}} method and the {{domxref("Worker.onmessage", "onmessage")}} event handler. When you want to send a message to the worker, you post messages to it like this (<a href="https://github.com/mdn/simple-web-worker/blob/gh-pages/main.js">main.js</a>):</p>
 
 <pre class="brush: js">first.onchange = function() {
-  myWorker.postMessage([first.value,second.value]);
+  myWorker.postMessage([first.value, second.value]);
   console.log('Message posted to worker');
 }
 
 second.onchange = function() {
-  myWorker.postMessage([first.value,second.value]);
+  myWorker.postMessage([first.value, second.value]);
   console.log('Message posted to worker');
 }</pre>