meta: add meta_factory to fwd file

src/entt/meta/factory.hpp

@@ -15,6 +15,7 @@
 #include "../core/type_traits.hpp"
 #include "../locator/locator.hpp"
 #include "context.hpp"
+#include "fwd.hpp"
 #include "meta.hpp"
 #include "node.hpp"
 #include "policy.hpp"

src/entt/meta/fwd.hpp

@@ -19,6 +19,9 @@ struct meta_func;
 
 class meta_type;
 
+template<typename>
+class meta_factory;
+
 } // namespace entt
 
 #endif