chore(deps): update pymdown-extensions requirement in /docs

Updates the requirements on [pymdown-extensions](https://github.com/facelessuser/pymdown-extensions) to permit the latest version.
- [Release notes](https://github.com/facelessuser/pymdown-extensions/releases)
- [Commits](facelessuser/pymdown-extensions@12.1...12.2)

---
updated-dependencies:
- dependency-name: pymdown-extensions
  dependency-version: '12.2'
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -10,4 +10,4 @@
 
 mkdocs>=1.6.1
 mkdocs-material>=9.7.7
-pymdown-extensions>=12.1
+pymdown-extensions>=12.2