feat: allow reserved snippet names when embedded in component

[trueadm]

This PR enables reserved names for snippets when they're embedded within a component.

<script>
	import Child from './Child.svelte';
</script>

<Child>
	{#snippet const()}
		<p>hello world</p>
	{/snippet}
</Child>

<script>
	const { const: const_snippet } = $props();
</script>

{@render const_snippet()}

[Rich-Harris]

preview: https://svelte-dev-git-preview-svelte-14150-svelte.vercel.app/

this is an automated message

[pkg-pr-new]

pnpm add https://pkg.pr.new/svelte@14150

commit: 140d6b1