build(deps): bump furo in /docs in the docs-dependencies group (#546)

Bumps the docs-dependencies group in /docs with 1 update: [furo](https://github.com/pradyunsg/furo).


Updates `furo` from 2025.7.19 to 2025.9.25
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2025.07.19...2025.09.25)

---
updated-dependencies:
- dependency-name: furo
  dependency-version: 2025.9.25
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: docs-dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -1,4 +1,4 @@
 Sphinx==8.2.3
 sphinx-autodoc-typehints==3.1.0
-furo==2025.7.19
+furo==2025.9.25
 myst-parser==4.0.1