chore: Form ref will also pass types to Form

Author: zombieJ

src/index.tsx

@@ -7,7 +7,7 @@ import FieldForm, { FormProps } from './Form';
 import { FormProvider } from './FormContext';
 
 const InternalForm = React.forwardRef<FormInstance, FormProps>(FieldForm) as <Values = any>(
-  props: React.PropsWithChildren<FormProps<Values>> & { ref?: React.Ref<FormInstance> },
+  props: React.PropsWithChildren<FormProps<Values>> & { ref?: React.Ref<FormInstance<Values>> },
 ) => React.ReactElement;
 
 type InternalForm = typeof InternalForm;