Communicates the intent a bit better

When the `permalink` option is passed to `useFormState`, and the form is
submitted before it has hydrated, the permalink will be used as the target
of the form action, enabling MPA-style form submissions.

(Note that submitting a form without hydration is a feature of Server Actions;
it doesn't work with regular client actions.)

It does not have any effect after the form has hydrated.