CSS selector removal causing style errors

[Rich-Harris]

REPL:

<!--<p class='foo'>foo</p>-->
<p class='bar'>bar</p>
<p class='baz'>baz</p>

<style>
	.foo, .bar, .baz {
		color: red;
	}
</style>

The .foo gets removed, but not the following comma, so this is the resulting broken CSS:

,.bar[svelte-680739708],.baz[svelte-680739708]{color:red}