Update sphinx-autodoc-typehints requirement from >=3.11.0 to >=3.12.0

Updates the requirements on [sphinx-autodoc-typehints](https://github.com/tox-dev/sphinx-autodoc-typehints) to permit the latest version.
- [Release notes](https://github.com/tox-dev/sphinx-autodoc-typehints/releases)
- [Commits](https://github.com/tox-dev/sphinx-autodoc-typehints/compare/3.11.0...3.12.0)

---
updated-dependencies:
- dependency-name: sphinx-autodoc-typehints
  dependency-version: 3.12.0
  dependency-type: direct:production
...

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

docs/requirements.txt

@@ -9,7 +9,7 @@ linkify-it-py>=2.1.0
 sphinx-autobuild>=2025.8.25
 sphinx-copybutton>=0.5.2
 sphinxext-opengraph>=0.13.0
-sphinx-autodoc-typehints>=3.11.0
+sphinx-autodoc-typehints>=3.12.0
 sphinx-sitemap>=2.9.0
 
 # Alternative modern theme (optional)