docs improvements

[benmccann]

Describe the problem

implement suggestions from #ambassadors

Describe the proposed solution

• untrack
• how to use interfaces with $props
• how to type a component (ReturnType<typeof Component>)
• links between tutorial and docs

Importance

nice to have

[rChaoz]

I would add "how to type and forward props to html elements", probably under the $props interface thing.

[shivan-s]

Don't know if this has been done or where to even mention this or if it has been mentioned.

In the docs, can we mention the "docstring/jsdoc/sveltedoc" feature:

<!--@component
	This component can do things
-->
<script>
 // svelte code
</script>

<div>I can do things</div>

Seems like a best kept secret.

[benmccann]

I just found https://github.com/sveltejs/svelte.dev/issues/747, which also mentions a lot of these issues