chore(deps): bump sphinx from 8.2.3 to 9.0.4 in /requirements

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.2.3 to 9.0.4.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/v9.0.4/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.2.3...v9.0.4)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-version: 9.0.4
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements/requirements_doc.txt

@@ -1,4 +1,4 @@
-Sphinx==8.2.3
+Sphinx==9.0.4
 ansys-sphinx-theme==1.6.3
 sphinx-copybutton==0.5.2
 sphinx_toolbox==4.1.0