feat!: remove as prop in favor of svelte:element

[metonym]

This was developed initially to address #1605. It removes the as prop, which was added before svelte:element was supported in Svelte. The purpose is to allow the consumer to customize the element tag.

However, this should not be merged since it has a flaw.

The issue is that $$restProps are spread to the element; the tag attributes in the generated types should be generic to match the tag. This is a limitation of sveld, which does not support generics in props.

Perhaps another reason to switch to TypeScript + @sveltejs/package (#1616)

[theetrain]

Thanks for exploring this. Usage of $$restProps seems essential in order for users to apply standard attributes to a component's canonical element. I'm also exploring svelte-package in #1629 and results look promising so far.

Since $$props and $$restProps are discouraged, maybe we should use a custom prop such as buttonAttributes for <Button /> and apply its respective HTML element type to that prop. At least it'll look more proper, can be documented, and hopefully can be optimized in the final Svelte output.

[metonym]

maybe we should use a custom prop such as buttonAttributes for <Button /> and apply its respective HTML element type to that prop. At least it'll look more proper, can be documented, and hopefully can be optimized in the final Svelte output.

That's a very elegant solution. +1