Allow relative paths in useFetcher submit and load

[nicholaschiang]

Right now, I have to:

  const status = useFetcher<DemonstrationsStatus>()
  const statusAction = useResolvedPath('api/status')
  useEffect(() => {
    if (status.type === 'init') status.load(statusAction.pathname)
  }, [status, statusAction.pathname])

It would be nice if I could just:

  const status = useFetcher<DemonstrationsStatus>()
  useEffect(() => {
    if (status.type === 'init') status.load('api/status')
  }, [status])

The useFetcher functions should accept the same paths as <Link> and behave similarly.