fix: Use version 4 for examples and tutorial (#8806)

* Use version 4 for examples and tutorial

* Remove redundant import

sites/svelte.dev/src/config.js

@@ -1,6 +1,6 @@
 // REPL props
 
-export const svelteUrl = `https://unpkg.com/svelte@3`;
+export const svelteUrl = `https://unpkg.com/svelte@4`;
 export const mapbox_setup = `window.MAPBOX_ACCESS_TOKEN = '${
 	import.meta.env.VITE_MAPBOX_ACCESS_TOKEN
 }';`;

sites/svelte.dev/src/routes/tutorial/[slug]/+page.svelte

@@ -6,8 +6,6 @@
 	import { mapbox_setup, svelteUrl } from '../../../config.js';
 	import TableOfContents from './TableOfContents.svelte';
 
-	import '@sveltejs/site-kit/styles/code.css';
-
 	export let data;
 
 	/** @type {import('@sveltejs/repl').default} */