Allows MathJax code to pass straight through to the output without wrapping an HTML element around it. Just a bit cleaner.

This uses the markdown module's "HTML stash" system to store the string so it doesn't get any additional Markdown processing applied. The <, >, and & characters are still translated to entities.

Here it is in action:

>>> import markdown, mdx_mathjax
>>> md = markdown.Markdown(extensions=[mdx_mathjax.MathJaxExtension()])
>>> print(md.convert('Hello, world! Here is some math: ${a}_b < c_{d}$'))
<p>Hello, world! Here is some math: ${a}_b &lt; c_{d}$</p>