fixup! Mark OpaqueWrappable specializations as final

Author: jasnell

src/workerd/jsg/promise.h

@@ -25,7 +25,9 @@ namespace workerd::jsg {
 template <typename T, bool = isGcVisitable<T>()>
 struct OpaqueWrappable;
 
-struct OpaqueWrappableBase: public Wrappable {
+#define DEFAULT_VISIBILITY __attribute__((visibility("default")))
+
+struct DEFAULT_VISIBILITY OpaqueWrappableBase: public Wrappable {
   kj::StringPtr jsgGetMemoryName() const override final {
     return "OpaqueWrappable"_kjc;
   }