Bump pymdown-extensions from 10.8.1 to 10.9 (microsoft#1883)

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.8.1 to 10.9.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.8.1...10.9)

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

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

requirements-docs.txt

@@ -1,6 +1,6 @@
 mkdocs==1.6.0
 mkdocs-material==9.5.31
-pymdown-extensions==10.8.1
+pymdown-extensions==10.9
 mike==2.1.2
 mkdocs-simple-hooks==0.1.5
 mkdocs-git-revision-date-localized-plugin==1.2.6