chore(deps): bump katex from 0.16.19 to 0.16.21 in /docs

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.16.19 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@v0.16.19...v0.16.21)

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

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

docs/yarn.lock

@@ -2674,9 +2674,9 @@ jsonpointer@^5.0.1:
   integrity sha512-p/nXbhSEcu3pZRdkW1OfJhpsVtW1gd4Wa1fnQc9YLiTfAjn0312eMKimbdIQzuZl9aa9xUGaRlP9T/CJE/ditQ==
 
 katex@^0.16.0:
-  version "0.16.19"
-  resolved "https://registry.yarnpkg.com/katex/-/katex-0.16.19.tgz#698e026188876f9c8c93d3ecb27b212aaa056d0a"
-  integrity sha512-3IA6DYVhxhBabjSLTNO9S4+OliA3Qvb8pBQXMfC4WxXJgLwZgnfDl0BmB4z6nBMdznBsZ+CGM8DrGZ5hcguDZg==
+  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"