fix: amend incorrect querySelector call

Author: Alex Nozdriukhin

src/prefetch.mjs

@@ -52,7 +52,7 @@ function linkPrefetchStrategy(url) {
     link.onload = resolve;
     link.onerror = reject;
 
-    (document.head || document.querySelector(`script`.parentNode)).appendChild(link);
+    (document.head || document.querySelector(`script`).parentNode).appendChild(link);
   });
 };