title: Rewrite rule to add .html suffix
body: <p>I am using WordPress. I need to add a custom rewriterule. I want to have two URLs for a single page.  </p>
  
  <p>For example:  </p>
  
  <blockquote>
    <p><strong>www.test.com/abc</strong> &lt;--- At present this is implemented &amp; working fine.</p>
    
    <p><strong>www.test.com/abc.html</strong> &lt;--- Need to add .html at back side.</p>
  </blockquote>
  
  <p>I want to allow access to the same page with <code>.html</code> extension.  </p>
  
  <p>How can I do that?</p>