const and tabs

test/runtime/samples/context-setcontext-return/main.svelte

@@ -1,7 +1,7 @@
 <script>
 	import { setContext } from 'svelte';
-    let a = {};
+	const a = {};
-    let b = setContext('foo', a);
+	const b = setContext('foo', a);
 </script>
 
 <div>{a === b}</div>