Markdown code blocks are double-blocked

Here's a current code block: https://f-droid.org/docs/Installing_the_Server_and_Repo_Tools/#debianubuntumintusw

The new Debian/buster build of the website has a weird double code block CSS effect:

The Debian/jessie build of the site generated this HTML from code blocks:

<div class="highlighter-rouge">
<pre class="highlight">
<code>sudo apt-get install fdroidserver</code>
</pre>
</div>

The new Debian/buster build generates and extra <div> level:

<div class="highlighter-rouge">
<div class="highlight">
<pre class="highlight">
<code>sudo apt-get install fdroidserver</code>
</pre>
</div>
</div>

@uniqx @redplanet I'm terrible at CSS but I imagine this isn't too hard to fix?