Updates the Stan submodule to bef9c85db.

stan-buildbot · stan-buildbot · commit 76742175f380 · 2024-05-12T05:25:30.000-04:00
diff --git a/stan b/stan
@@ -1 +1 @@
-Subproject commit 607474b7799d64637487705d65a67027368819e7
+Subproject commit bef9c85db40013918b23602153432e2ecd7d0e94
