Output HTML as plain text for code example

Question

I have an application Im building that needs to output some HTML inside a <pre> and <code> tag. I am using prism for the syntax highlighting and it works fine for other languages. The problem is that when I use HTML inside the code tag it either renders the html, or won't highlight with prism because it is output as a string.

The markup is:

<pre>
<code class="language-markup">
  <form class="send-to-mobile" method="post">
    <input type="text" pattern="[0-9]*" name="phone_number" class="phone_number" />
    <input type="submit" value="Text Me" />
  </form>
  <div class="thanks-message">
    <p>The link will be delivered momentarily</p>
  </div>
</code>
</pre>