chore(deps): update dependency pymdown-extensions to v9

Signed-off-by: Renovate Bot <bot@renovateapp.com>

Author: renovate-bot

docs/requirements.txt

@@ -1,4 +1,4 @@
 mkdocs==1.2.3
 mkdocs-material==7.3.6
-pymdown-extensions==8.2
+pymdown-extensions==9.1
 mdx_truly_sane_lists==1.2