markdown-it-attrs not working for code fences

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Tell us about your environment

• MarkBind Version:

What did you do? Please include the actual source code causing the issue.

```js {.someClass }
const js = 1;
```

What did you expect to happen?

<pre><code class="hljs js someClass"><span class="hljs-keyword">const</span> js = <span class="hljs-number">1</span>;
</code></pre>

What actually happened? Please include the actual, raw output.

<pre><code class="hljs js"><span class="hljs-keyword">const</span> js = <span class="hljs-number">1</span>;
</code></pre>

Markdown-it-attrs are not being rendered, someClass did not get added.