Update visitor with parenthesized const expressions
diff --git a/src/visit.rs b/src/visit.rs
index 6ae2824..b9fd8fb 100644
--- a/src/visit.rs
+++ b/src/visit.rs
@@ -283,5 +283,8 @@
         ConstExpr::Path(ref path) => {
             visitor.visit_path(path);
         }
+        ConstExpr::Paren(ref expr) => {
+            visitor.visit_const_expr(expr);
+        }
     }
 }