Document that `initial: 0` waits for user to dismiss toast

[tv42]

I had to reverse engineer this from the component example on https://zerodevx.github.io/svelte-toast/:

svelte-toast/docs/App.svelte

Lines 247 to 262 in 9d234a7

	{
	name: 'SEND COMPONENT AS A MESSAGE',
	code: `toast.push({
	component: {
	src: DummyComponent, // where \`src\` is a Svelte component
	props: {
	title: 'A Dummy Cookie Component'
	},
	sendIdTo: 'toastId' // send toast id to \`toastId\` prop
	},
	dismissable: false,
	initial: 0,
	theme: {
	'--toastPadding': '0',
	'--toastMsgPadding': '0'
	}

[zerodevx]

Added additional examples (and extra comments) in the demo that would hopefully help clarify.