Update sphinx-autodoc-typehints requirement (#70)

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](tox-dev/sphinx-autodoc-typehints@1.24.0...3.5.1)

---
updated-dependencies:
- dependency-name: sphinx-autodoc-typehints
  dependency-version: 3.5.1
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -1,5 +1,5 @@
 sphinx>=7.4,<8.3
-sphinx-autodoc-typehints>=1.24,<3.3
+sphinx-autodoc-typehints>=1.24,<3.6
 sphinx-rtd-theme>=2.0.0,<3.0.3
 docutils<0.23
 sphinx-copybutton