Bump the python-packages group across 1 directory with 3 updates

Bumps the python-packages group with 3 updates in the / directory: [furo](https://github.com/pradyunsg/furo), [blacken-docs](https://github.com/asottile/blacken-docs) and [black](https://github.com/psf/black).


Updates `furo` from 2024.8.6 to 2025.7.19
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2024.08.06...2025.07.19)

Updates `blacken-docs` from 1.19.1 to 1.20.0
- [Changelog](https://github.com/adamchainz/blacken-docs/blob/main/CHANGELOG.rst)
- [Commits](adamchainz/blacken-docs@1.19.1...1.20.0)

Updates `black` from 25.1.0 to 25.9.0
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](psf/black@25.1.0...25.9.0)

---
updated-dependencies:
- dependency-name: furo
  dependency-version: 2025.7.19
  dependency-type: direct:development
  update-type: version-update:semver-major
  dependency-group: python-packages
- dependency-name: blacken-docs
  dependency-version: 1.20.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
- dependency-name: black
  dependency-version: 25.9.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
...

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

Author: dependabot[bot]

setup.py

@@ -69,7 +69,7 @@ def get_version():
     extras_require={
         "docs": [
             "Sphinx==7.4.7",
-            "furo==2024.8.6",
+            "furo==2025.9.25",
             "sphinx-autobuild",
             "codespell>=2.2.5",
             "blacken-docs",
@@ -82,8 +82,8 @@ def get_version():
             "pytest-xdist>=2.2.1",
             "pytest-asyncio>=1.2.0",
             "beautifulsoup4>=4.8.1",
-            "black==25.1.0",
-            "blacken-docs==1.19.1",
+            "black==25.9.0",
+            "blacken-docs==1.20.0",
             "pytest-timeout>=1.4.2",
             "trustme>=0.7",
             "cogapp>=3.3.0",