chore(deps): update dependency sphinx to v9.1.0 (#379)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

docs/requirements.txt

@@ -1,2 +1,2 @@
-sphinx==9.0.4
+sphinx==9.1.0
 furo==2025.12.19