Use passive listeners in prefetch (#4207)

* Use passive listeners in prefetch

Without passive=true, Lighthouse complains about not using passive listeners to improve scrolling performance.

* Create cold-shoes-drum.md

Co-authored-by: Nate Moore <[email protected]>

Author: jablonski

.changeset/cold-shoes-drum.md

@@ -0,0 +1,5 @@
+---
+"@astrojs/prefetch": patch
+---
+
+Use `passive` event listeners for performance

packages/integrations/prefetch/src/client.ts

@@ -25,7 +25,7 @@ let observer: IntersectionObserver;
 function observe(link: HTMLAnchorElement) {
 	preloaded.add(link.href);
 	observer.observe(link);
-	events.map((event) => link.addEventListener(event, onLinkEvent, { once: true }));
+	events.map((event) => link.addEventListener(event, onLinkEvent, { passive:true, once: true }));
 }
 
 function unobserve(link: HTMLAnchorElement) {