chore(deps): bump katex from 0.16.11 to 0.16.21 in /website

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.16.11 to 0.16.21.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](KaTeX/KaTeX@v0.16.11...v0.16.21)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

website/yarn.lock

@@ -10270,13 +10270,13 @@ __metadata:
   linkType: hard
 
 "katex@npm:^0.16.9":
-  version: 0.16.11
-  resolution: "katex@npm:0.16.11"
+  version: 0.16.21
+  resolution: "katex@npm:0.16.21"
   dependencies:
     commander: "npm:^8.3.0"
   bin:
     katex: cli.js
-  checksum: be405d45d7228bbfeecd491e0f74d9da0066b5e7b457e3f1dc833de5b63f9e98e40d2ef6b46e1cbe577490a43338c043851da032c45aeec0cc03ad431ef6fd83
+  checksum: e2e4139ba72a13f2393308fbb2b4c5511611a19a40a6e39d956cf775e553af3517dbfd0a54477faaf401c923e4654e32296347846b8ff15dfa579f88ff8579bb
   languageName: node
   linkType: hard