Update config parser to support export default with identifier and add SvelteKit code

Co-authored-by: NatoBoram <natoboram@users.noreply.github.com>

src/fixtures/sveltekit/default.js

@@ -0,0 +1,10 @@
+import adapter from '@sveltejs/adapter-auto'
+
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+  kit: {
+    adapter: adapter()
+  }
+}
+
+export default config