Fixes consistency issues between markdown and code in tutorial\02\01\05

Author: Tellev

apps/svelte.dev/content/tutorial/02-advanced-svelte/01-advanced-reactivity/05-stores/+assets/app-a/src/lib/shared.js

@@ -1 +1 @@
-export let count = 0;
+export const count = 0;

apps/svelte.dev/content/tutorial/02-advanced-svelte/01-advanced-reactivity/05-stores/+assets/app-b/src/lib/shared.js

@@ -1,3 +1,3 @@
 import { writable } from 'svelte/store';
 
-export let count = writable(0);
+export const count = writable(0);