Update dependency sphinx to v9

renovate[bot] · web-flow · commit 3fd073604a5e · 2025-12-31T16:25:24.000Z
diff --git a/docs/requirements.txt b/docs/requirements.txt
@@ -1,3 +1,3 @@
 Pygments==2.19.2
-sphinx==8.2.3
+sphinx==9.1.0
 sphinx_rtd_theme==3.0.2
