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

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] <[email protected]>

Author: dependabot[bot]

docs/yarn.lock

@@ -5636,9 +5636,9 @@ jsonfile@^6.0.1:
     graceful-fs "^4.1.6"
 
 katex@^0.16.9:
-  version "0.16.11"
-  resolved "https://registry.yarnpkg.com/katex/-/katex-0.16.11.tgz#4bc84d5584f996abece5f01c6ad11304276a33f5"
-  integrity sha512-RQrI8rlHY92OLf3rho/Ts8i/XvjgguEjOkO1BEXcU3N8BqPpSzBNwV/G0Ukr+P/l3ivvJUE/Fa/CwbS6HesGNQ==
+  version "0.16.21"
+  resolved "https://registry.yarnpkg.com/katex/-/katex-0.16.21.tgz#8f63c659e931b210139691f2cc7bb35166b792a3"
+  integrity sha512-XvqR7FgOHtWupfMiigNzmh+MgUVmDGU2kXZm899ZkPfcuoPuFxyHmXsgATDpFZDAXCI8tvinaVcDo8PIIJSo4A==
   dependencies:
     commander "^8.3.0"