Support for Math in GitLab Flavored Markdown

[stephanlachnit]

GitLab has the possibility to display math both inline as in code blocks using LaTeX (renderd via KaTeX, see e.g. here).

The syntax:

Inline math: $`a^2+b^2=c^2`$.

Math block:
```math
a^2+b^2=c^2
```

This means that the GitLab syntax directly interferes with normal code blocks (i.e. math needs to take priority over code). While there is the MathJax extension, it does not support the GitLab Syntax.

It would be nice to have a built-in extension.Math extension that would support the GitLab syntax for math. I'm sure some of the code from the MathJax extension could be reused for this.