Double highlighted code block

[Juice-Han]

When I coded like this

```javascript
/* Some pointless Javascript */
var rawr = ["r", "a", "w", "r"];
```

After 'jekyll serve', my local site showed me double highlighted code block like this

so I checked the html file and found

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="cm">/* Some pointless Javascript */</span>
<span class="kd">var</span> <span class="nx">rawr</span> <span class="o">=</span> <span class="p">[</span><span class="dl">"</span><span class="s2">r</span><span class="dl">"</span><span class="p">,</span> <span class="dl">"</span><span class="s2">a</span><span class="dl">"</span><span class="p">,</span> <span class="dl">"</span><span class="s2">w</span><span class="dl">"</span><span class="p">,</span> <span class="dl">"</span><span class="s2">r</span><span class="dl">"</span><span class="p">];</span>
</code></pre></div></div>

How to delete outside block of the code block?