chore(deps): bump sphinx from 8.2.3 to 9.0.4

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] <support@github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -259,9 +259,9 @@ soupsieve==2.8 \
     --hash=sha256:0cc76456a30e20f5d7f2e14a98a4ae2ee4e5abdc7c5ea0aafe795f344bc7984c \
     --hash=sha256:e2dd4a40a628cb5f28f6d4b0db8800b8f581b65bb380b97de22ba5ca8d72572f
     # via beautifulsoup4
-sphinx==8.2.3 \
-    --hash=sha256:398ad29dee7f63a75888314e9424d40f52ce5a6a87ae88e7071e80af296ec348 \
-    --hash=sha256:4405915165f13521d875a8c29c8970800a0141c14cc5416a38feca4ea5d9b9c3
+sphinx==9.0.4 \
+    --hash=sha256:594ef59d042972abbc581d8baa577404abe4e6c3b04ef61bd7fc2acbd51f3fa3 \
+    --hash=sha256:5bebc595a5e943ea248b99c13814c1c5e10b3ece718976824ffa7959ff95fffb
     # via
     #   kio-docs (pyproject.toml)
     #   furo