Make sure code block overflow scrolls

[HaSistrunk]

Describe the bug

As seen in in the API Docs, code blocks are not handling overflow.

Expected behavior

If the code is going outside the container, the box should instead scroll to see the rest of the content instead of overflowing out of the box.

Impact on your work

Looks bad and does not instill confidence in the content.

Additional context

We should just be able to add overflow: scroll; to the .highlight class to fix this.