build(deps): bump pygments from 2.19.2 to 2.20.0 in /docs

Bumps [pygments](https://github.com/pygments/pygments) from 2.19.2 to 2.20.0.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.19.2...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

@@ -1,7 +1,7 @@
 Babel==2.17.0
 Jinja2==3.1.6
 MarkupSafe==3.0.3
-Pygments==2.19.2
+Pygments==2.20.0
 Sphinx==7.4.7
 certifi==2026.1.4
 chardet==5.2.0