update docs context to svelte 5

src/routes/docs/tutorials/+layout.svelte

@@ -2,12 +2,18 @@
     import { page } from '$app/state';
     import Docs, { type DocsLayoutVariant } from '$lib/layouts/Docs.svelte';
     import Sidebar from '../Sidebar.svelte';
+    interface Props {
+        children?: import('svelte').Snippet;
+    }
 
-    $: variant =
-        page.route.id === '/docs/tutorials' ? 'default' : ('two-side-navs' as DocsLayoutVariant);
+    let { children }: Props = $props();
+
+    let variant = $derived(
+        page.route.id === '/docs/tutorials' ? 'default' : ('two-side-navs' as DocsLayoutVariant)
+    );
 </script>
 
 <Docs {variant}>
     <Sidebar />
-    <slot />
+    {@render children?.()}
 </Docs>