Updates the Stan submodule to 8b3b76f62.

stan-buildbot · stan-buildbot · commit 0587c3758452 · 2026-05-15T12:05:33.000-04:00
diff --git a/stan b/stan
@@ -1 +1 @@
-Subproject commit 103ff645a923b2d806cfdc9fe425a5b9b084e3ea
+Subproject commit 8b3b76f623e7fab2b2b70850fd486a53b1558294
