Bump mistune from 3.0.2 to 3.2.1 in /docs

Bumps [mistune](https://github.com/lepture/mistune) from 3.0.2 to 3.2.1.
- [Release notes](https://github.com/lepture/mistune/releases)
- [Changelog](https://github.com/lepture/mistune/blob/main/docs/changes.rst)
- [Commits](lepture/mistune@v3.0.2...v3.2.1)

---
updated-dependencies:
- dependency-name: mistune
  dependency-version: 3.2.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/notebook_requirements.txt

@@ -24,7 +24,7 @@ jupyter-core==5.7.2
 jupyterlab-pygments==0.3.0
 lxml==5.3.0
 MarkupSafe==2.1.5
-mistune==3.0.2
+mistune==3.2.1
 nbclient==0.10.0
 nbconvert==7.17.0
 nbformat==5.10.4