Bump katex from 0.16.15 to 0.16.18

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.16.15 to 0.16.18.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](KaTeX/KaTeX@v0.16.15...v0.16.18)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>