Update dependency pymdown-extensions to v10.9

| datasource | package            | from   | to   |
| ---------- | ------------------ | ------ | ---- |
| pypi       | pymdown-extensions | 10.8.1 | 10.9 |


Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

docs/requirements.txt

@@ -5,7 +5,7 @@ mkdocs-material==9.5.18
 
 # Markdown extensions
 Pygments==2.18.0
-pymdown-extensions==10.8.1
+pymdown-extensions==10.9
 
 # MkDocs plugins
 mkdocs-material-extensions==1.3.1