refactor: use $$restProps API

- add ref prop for applicable components (#196)
- add slot to Content Switcher `Switch` component (#183)
- remove fillArray, css utilities

src/components/StructuredList/StructuredList.svelte

@@ -1,20 +1,15 @@
 <script>
-  let className = undefined;
-  export { className as class };
   export let selected = undefined;
   export let border = false;
   export let selection = false;
-  export let style = undefined;
 
-  import { createEventDispatcher, setContext } from 'svelte';
-  import { writable } from 'svelte/store';
-  import { cx } from '../../lib';
+  import { createEventDispatcher, setContext } from "svelte";
+  import { writable } from "svelte/store";
 
   const dispatch = createEventDispatcher();
+  const selectedValue = writable(selected);
 
-  let selectedValue = writable(selected);
-
-  setContext('StructuredListWrapper', {
+  setContext("StructuredListWrapper", {
     selectedValue,
     update: value => {
       selectedValue.set(value);
@@ -22,18 +17,18 @@
   });
 
   $: selected = $selectedValue;
-  $: {
-    dispatch('change', $selectedValue);
-  }
+  $: dispatch("change", $selectedValue);
 </script>
 
 <section
+  aria-label="Structured list section"
+  class:bx--structured-list={true}
+  class:bx--structured-list--border={border}
+  class:bx--structured-list--selection={selection}
+  {...$$restProps}
   on:click
   on:mouseover
   on:mouseenter
-  on:mouseleave
-  aria-label={$$props['aria-label'] || 'Structured list section'}
-  class={cx('--structured-list', border && '--structured-list--border', selection && '--structured-list--selection', className)}
-  {style}>
+  on:mouseleave>
   <slot />
 </section>