Hello smart people!

With all the talk about Emacs 29, I figured we should update Org Mode to
use MathJax 3, to catch up with the rest of the world.

From the documentation (for MathJax 3.0 released in 2019):

> Version 3.0 of MathJax is a complete rewrite of MathJax from the
> ground up, and its usage and configuration is significantly different
> from that of MathJax version 2.

In practice, MathJax 3.2 renders mathematics faster and better, plus it
significantly improves LaTeX support.  For instance, one can typeset
calculus with the built-in (!) 'physics' package, like in LaTeX.

More information on the recent progress (made in 2019-2021):

https://docs.mathjax.org/en/latest/upgrading/whats-new-3.0.html
https://docs.mathjax.org/en/latest/upgrading/whats-new-3.1.html
https://docs.mathjax.org/en/latest/upgrading/whats-new-3.2.html

See the attached [working, but WIP] patch.

My question for you:

How do we change the 'org-html-mathjax-options'?

- 'scale' has now the value in [0, 1] and not in [0, 100]
- 'scale' should exist as a number and not string
- 'font' did not make it to MathJax 3 [*]
- 'linebreaks' did not make it to MathJax 3 [*]
- 'autonumber' has the values in lowercase now
- 'autonumber' became 'tags' in MathJax terminology

[*] coming in MathJax 4, currently in alpha

How does Org mode approach these kind of breaking changes?

Rudy