clarify svelte:component migration, avoids common gotcha

[rgon]

Clarify docs to specify that, while svelte:component is no longer needed and deprecated, capitalizing the component variable name is required to avoid mismatching types.

Avoids users doing the same gotcha that I stumbled upon, it will be a common oversight when refactoring existing codebases: sveltejs/svelte#13795

As evidenced in these docs themselves (corrected):

...
	let component: Component<{ foo: string }> = $state(
		Math.random() ? ComponentA : ComponentB
	);
</script>

<svelte:component this={component} foo="bar" />

[vercel]

Someone is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[benmccann]

PRs should go to https://github.com/sveltejs/svelte/tree/main/documentation

[dummdidumm]

Thank you - as Ben points out, the change should happen in the svelte repo, which will eventually be synced in here

[rgon]

Thanks, moved to sveltejs/svelte#13835