Bump pygments from 2.16.1 to 2.20.0 in /docs

Bumps [pygments](https://github.com/pygments/pygments) from 2.16.1 to 2.20.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.16.1...2.20.0)

---
updated-dependencies:
- dependency-name: pygments
  dependency-version: 2.20.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -10,7 +10,7 @@ importlib-metadata==6.8.0
 Jinja2==3.1.6
 packaging==23.1
 pycparser==2.21
-Pygments==2.16.1
+Pygments==2.20.0
 requests==2.33.0
 six==1.16.0
 snowballstemmer==2.2.0