Apply suggestions from code review

Author: Rich-Harris

packages/svelte/tests/runtime-runes/samples/snippet-optional-arguments-defaults/_config.js

@@ -2,6 +2,5 @@ import { flushSync } from 'svelte';
 import { test } from '../../test';
 
 export default test({
-	html: '012',
-	ssrHtml: '012'
+	html: '013'
 });

packages/svelte/tests/runtime-runes/samples/snippet-optional-arguments-defaults/main.svelte

@@ -1,5 +1,5 @@
-{#snippet snip(a, b = 1, c=2)}
-{a}{b}{c}
+{#snippet snip(a, b = 1, c = (2, 3))}
+	{a}{b}{c}
 {/snippet}
 
 {@render snip(0)}