Add store to detect query changing

[ykrods]

This will add a store to detect changes that the URL (including query string or hash) has been modified.

Routing depends on path (location.pathname) as same as before.

Example

<script>
  import { currentURL } from "svelte-spa-history-router";

  $: name = $currentURL.searchParams.get("name") || 'unknown';
</script>
<div>{ name }</div>

Note

Assumed use case likes giving initial selected value to search (filter) form from a link. but it may be a better solution to use store (in trial)