Regex for params

[ambrt]

Regex pattern matching could useful for routes.
It was mentioned here #76 (comment)

Basically its possible to make catch-all parent module and do regex matching by hand like

App.svelte
   <Route path=":catchall" let:params>
      <Parent {params} />
    </Route>

Parent.svelte
<script>
export let params
//import pages...
</script>
{#if /[0-9]{1,}/.test(params.catchall)}
  <Numbers params={params} />
{/if}
{#if /[a-z]{1,}/.test(params.catchall)}
  <Letters params={params} />
{/if}