mathjax is incomplete

[HuStmpHrrr]

in particular, it doesn't support enough mathjax to support inference rules, or elements marked as math class.

the ultimate reason comes from https://github.com/ocaml-sf/learn-ocaml/tree/master/static/js/mathjax/jax/input

which does not include the tex.js script:

https://github.com/mathjax/MathJax/tree/master/es5/input

why just copy a partial mathjax? can we get this fixed?