diff --git a/vendor/grammars-v4 b/vendor/grammars-v4
index 284602b..923a1a9 160000
--- a/vendor/grammars-v4
+++ b/vendor/grammars-v4
@@ -1 +1 @@
-Subproject commit 284602b3f23ca54dc30778204ab7ae9e969145e9
+Subproject commit 923a1a90f3b9e28c8ac08e170e582ceb15d6f0a9