chore: bump pymdown-extensions from 10.7.1 to 10.9

Bumps [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) from 10.7.1 to 10.9.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@10.7.1...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]>

requirements.docs.txt

@@ -2,4 +2,4 @@ markdown-include==0.8.1
 mkdocs-material-extensions==1.3.1
 mkdocs-material==9.5.15
 mkdocs==1.5.3
-pymdown-extensions==10.7.1
+pymdown-extensions==10.9