Update Transition Tutorial

The `fade` import was removed in the previous chapter, it needs to be re-added for the example to work correctly.

site/content/tutorial/10-transitions/03-in-and-out/app-a/App.svelte

@@ -1,5 +1,5 @@
 <script>
-	import { fly } from 'svelte/transition';
+	import { fade, fly } from 'svelte/transition';
 	let visible = true;
 </script>
 
@@ -12,4 +12,4 @@
 	<p transition:fly="{{ y: 200, duration: 2000 }}">
 		Flies in and out
 	</p>
-{/if}
+{/if}