build: Bump sphinx from 7.3.6 to 7.3.7 in /requirements

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.3.6 to 7.3.7.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.3.6...v7.3.7)

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

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

requirements/requirements_doc.txt

@@ -1,6 +1,6 @@
 ansys-sphinx-theme==0.15.2
 pyyaml==6.0.1
-Sphinx==7.3.6
+Sphinx==7.3.7
 sphinx-copybutton==0.5.2
 sphinx-jinja==2.0.2
 sphinx_design==0.5.0