Update adapter fallback file name

Changed the SvelteKit adapter fallback file from index.html to fallback.html in svelte.config.js to reflect the new fallback file.

Author: ehsan18t

svelte.config.js

@@ -6,15 +6,15 @@ import { vitePreprocess } from "@sveltejs/vite-plugin-svelte";
 
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
-	preprocess: vitePreprocess(),
-	kit: {
-		adapter: adapter({
-			fallback: "index.html"
-		}),
-		alias: {
-			"@/*": "src/*"
-		}
-	}
+  preprocess: vitePreprocess(),
+  kit: {
+    adapter: adapter({
+      fallback: "fallback.html",
+    }),
+    alias: {
+      "@/*": "src/*",
+    },
+  },
 };
 
 export default config;