Bump pymdown-extensions from 10.21 to 10.21.2 (#3740)

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.21 to 10.21.2.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.21...10.21.2)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements-docs.txt

@@ -1,6 +1,6 @@
 mkdocs==1.6.1
 mkdocs-material==9.7.6
-pymdown-extensions==10.21
+pymdown-extensions==10.21.2
 mike==2.1.4
 mkdocs-git-revision-date-localized-plugin==1.5.1
 mkdocs-git-committers-plugin-2==2.5.0