chore(deps): Bump pymdown-extensions from 10.16.1 to 10.21.2

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.16.1 to 10.21.2.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.16.1...10.21.2)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-version: 10.21.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -3,7 +3,7 @@ markdown==3.8.1
 mkdocs-material==9.7.6
 
 # Markdown extensions
-pymdown-extensions==10.16.1
+pymdown-extensions==10.21.2
 
 # MkDocs plugins
 mkdocs-meta-descriptions-plugin==3.0.0