pandoc markdown code blocks

[arve0]

Hi!
So if one use pandoc, this code:

```js
var int = 0;
```

will render to this HTML:

<pre class="js">
  <code>var int = 0;</code>
</pre>

which means getLanguage(element) will fail.

As I think this is a common setup, would you approve a PR for a getLanguage(element) that also looks into if element got a parent which is <pre> with a language class?

[arve0]

Adding, that class would not be prefixed with lang-.

[arve0]

I might also look into using metallic before the pandoc plugin..

[arve0]

Using metallic resolved my issue.