Make formAction return inferrable

[gustavoguichard]

Whenever we return the formAction in an action:

export async function action({ request }: ActionArgs) {
  return formAction( // ...)
}

export default function() {
  const actionData = useActionData<typeof action>()
  //         ^? any
}

The useActionData loses the inference - it will be inferred as any.

It'd be cool that it would infer the TypedResponse for us.
The inferred type should probably be a union of:

{ errors: FormErrors<SchemaType>, values: FormValues<SchemaType> } | UnpackData<typeof mutation>

Things to consider:

• If we use a custom json in createFormAction we should be using the return of that given function
• If we set a successPath in the formAction the return type of the mutation should not be considered:

{ errors: FormErrors<SchemaType>, values: FormValues<SchemaType> }

[gustavoguichard]

I'd be happy to pair on this one ;)