Update dependency Sphinx to v9 (#134)

renovate[bot] · web-flow · commit 932167ba03b0 · 2025-12-29T14:59:16.000+01:00
Co-authored-by: renovate[bot] &lt;29139614+renovate[bot]@users.noreply.github.com&gt;
diff --git a/docs/requirements.txt b/docs/requirements.txt
@@ -1,2 +1,2 @@
-Sphinx~=8.2.3
+Sphinx~=9.0.4
 furo==2025.12.19
