Unsupported language cause html in code blocks to be rendered as html, not text

[mrjones2014]

For example, the following markdown snippet will render an actual button, instead of the html as text:

Unsupported languages should at least attempt to escape html.

[mrjones2014]

this is a breaking issue for me so I ended up using a custom solution using Prism.js to handle syntax highlighting. Please fix in the future.