Fix InlineNotification and ToastNotification timeout

* Dispatch close event when a notification closes due to timeout
* Fix documentation text on the timeout prop (its removing the notification after opening it, not after closing it)

src/Notification/InlineNotification.svelte

@@ -17,6 +17,12 @@
    */
   export let lowContrast = false;
 
+  /**
+   * Set the timeout duration (ms) to hide the notification after opening it
+   * @type {number} [timeout=0]
+   */
+  export let timeout = 0;
+
   /**
    * Set the `role` attribute
    * @type {string} [role="alert"]
@@ -54,7 +60,23 @@
 
   const dispatch = createEventDispatcher();
 
-  $: open = true;
+  let open = true;
+  let timeoutId = undefined;
+
+  function close() {
+    open = false;
+    dispatch('close');
+  }
+
+  onMount(() => {
+    if (timeout) {
+      timeoutId = setTimeout(() => close(), timeout);
+    }
+
+    return () => {
+      clearTimeout(timeoutId);
+    };
+  });
 </script>
 
 {#if open}
@@ -81,10 +103,7 @@
       <NotificationButton
         {iconDescription}
         {notificationType}
-        on:click={() => {
-          open = false;
-          dispatch('close');
-        }} />
+        on:click={close()} />
     {/if}
   </div>
 {/if}