Bump mathjax from 3.2.2 to 4.0.0

Bumps [mathjax](https://github.com/mathjax/MathJax) from 3.2.2 to 4.0.0.
- [Release notes](https://github.com/mathjax/MathJax/releases)
- [Commits](https://github.com/mathjax/MathJax/compare/3.2.2...4.0.0

)

---
updated-dependencies:
- dependency-name: mathjax
  dependency-version: 4.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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