Apply suggestions from code review

Author: Rich-Harris

apps/svelte.dev/content/tutorial/04-advanced-sveltekit/03-link-options/01-preload/+assets/app-a/src/routes/+layout.svelte

@@ -8,7 +8,7 @@
 	let end = $state();
 
 	$effect(() => {
-		if (navigating) {
+		if (navigating.to) {
 			start = Date.now();
 			end = null;
 			previous = navigating;

apps/svelte.dev/content/tutorial/04-advanced-sveltekit/03-link-options/01-preload/+assets/app-b/src/routes/+layout.svelte

@@ -8,7 +8,7 @@
 	let end = $state();
 
 	$effect(() => {
-		if (navigating) {
+		if (navigating.to) {
 			start = Date.now();
 			end = null;
 			previous = navigating;