Bump sphinx from 8.0.2 to 8.1.2

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.0.2 to 8.1.2.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.0.2...v8.1.2)

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

Signed-off-by: dependabot[bot] <support@github.com>

pyproject.toml

@@ -60,7 +60,7 @@ dev = [
 docs = [
     "furo == 2024.8.6",
     "pyenchant == 3.2.2",
-    "sphinx == 8.0.2",
+    "sphinx == 8.1.2",
     "sphinx_tabs == 3.4.5",
     "sphinx-autobuild == 2024.10.3",
     "sphinx-copybutton == 0.5.2",