title: Storybook for React to show plain HTML source code with <Preview> Addon
body: <p>I am using <a href="https://storybook.js.org/docs/react/writing-docs/build-documentation" rel="nofollow noreferrer">Preview</a> addon in Storybook for React to show the component usage in Docs.</p>
  <pre><code>&lt;Preview withToolbar&gt;
    &lt;Story name=&quot;primary&quot;&gt;
    &lt;PrimaryButton  disabled={boolean(&quot;Disabled&quot;,false)} modifiers={[&quot;small&quot;]} onClick={action('button-click')} &gt; {text(&quot;Label&quot;, &quot;Hello Storybook&quot;)}&lt;/PrimaryButton&gt;
    &lt;/Story&gt;
  &lt;/Preview&gt;
  </code></pre>
  <p>This generate doc as below :
  <a href="https://i.stack.imgur.com/jtd2q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jtd2q.png" alt="enter image description here" /></a>
  There is a show code/ hide code switch which shows the React Code for the component , is it possible to show the plain HTML markup as well.</p>
  <p>I need to use a single storybook component explorer for React and non React Projects so wanted to check if plain markup source code be generated as well.</p>
  <p>Thanks</p>