Invalid HTML conversion `$'` in code block

[thino-rma]

$' in code block produces Invalid HTML which contains @@footer, closing body tag, closing html tag

OS: Windows 10 Pro Version: Haroopad v0.13.1

An example : sample.md contains only 3 lines. ``` $' ```

exported HTML: sample.html (showing only html under body tag)

<pre><code data-origin="<pre><code>

<footer style="position:fixed; font-size:.8em; text-align:right; bottom:0px; margin-left:-25px; height:20px; width:100%;">generated by <a href="http://pad.haroopress.com" target="_blank">haroopad</a></footer>
</body>
</html>

</code></pre>">

@@footer
</body>
</html>

</code></pre>

@@footer