fix links for local static files

src/lib/Link.svelte

@@ -10,20 +10,35 @@
             return null;
         }
     }
+
+    function ext(url) {
+
+    }
 </script>
 
 <script>
     export let href;
-    export let rel = '';
+    export let rel = null;
+
+    let url = null;
+    try {
+        url = new URL(href);
+    }
+    catch {}
+
+    let isLocal = false;
+    if (href.startsWith('/') || url?.host === $page.url.host) {
+        isLocal = true;
+    }
+
+    // if href is not a valid url, assume that it's a relative link
+    const path = url?.pathname || href;
+    // set rel="external" on links to static files (i.e. local links with a dot in them)
+    if (isLocal && path.search(/\.\w+$/) > -1) {
+        rel = 'external';
+    }
 </script>
 
-
-{#if href.startsWith('/') || host(href) === $page.host}
-    <a data-sveltekit-preload-data="hover" {href} {rel}>
-        <slot></slot>
-    </a>
-{:else}
-    <a {href}>
-        <slot></slot>
-    </a>
-{/if}
+<a data-sveltekit-preload-data={isLocal ? 'hover' : null} {href} {rel}>
+    <slot></slot>
+</a>