Fix svelte type

Author: lachlancollins

examples/svelte/simple/src/main.ts

@@ -2,7 +2,7 @@ import './app.css'
 import App from './App.svelte'
 
 const app = new App({
-  target: document.getElementById('app'),
+  target: document.getElementById('app')!,
 })
 
 export default app