title: PHP preg_replace html comments with empty space
body: <p>I have a bit of php code like this: </p>
  
  <pre><code>$test = "&lt;!--my comment goes here--&gt; Hello World";
  </code></pre>
  
  <p>Now i want to strip the whole html comment from the string, i know i need to use preg_replace, but now sure on the regex to go in there. 
  Can anybody help?
  Thanks</p>