Update sphinx requirement from <8,>=7.4.7 to >=7.4.7,<9

Updates the requirements on [sphinx](https://github.com/sphinx-doc/sphinx) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/v8.0.2/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.4.7...v8.0.2)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
...

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

pyproject.toml

@@ -39,7 +39,7 @@ localization = ["polib>=1.2.0, <2"]
 crontrigger = ["croniter>=3.0.3, <4"]
 dev = ["nox==2024.4.15"]
 "dev.docs" = [
-    "sphinx>=7.4.7, <8",
+    "sphinx>=7.4.7, <9",
     "furo==2024.8.6",
     "myst-parser>=3.0.1, <4",
     "sphinx-copybutton>=0.5.2, <1",