Upgrade svelte

[benjavicente]

This PR upgrades Svelte to use svelte:element in the Render component, removing the monstrosity that was needed to use the as={element} prop.

pd: thank you for the awesome port of the Headless UI 🚀

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/rgossiaux/svelte-headlessui/6NkCMS8UYPUoJzvrHRJGfuyuwVem
✅ Preview: https://svelte-headlessui-git-fork-benjavicente-chore-dc24ec-rgossiaux.vercel.app

[benjavicente]

Some other notes:

• isValidElement probably should be changed to something that validates if the as prop is a string or a component, like the official library.
• as prop could have autocompletion with keyof HTMLElementTagNameMap instead of using a custom array.
• There seems to be missing tests in of Render.svelte because svelte components are not tested as a as prop (all tests passed with svelte:component removed). In tests, toMatchInlineSnapshot is causing me some issues with indentation in the snapshots, so until that is fixed, this PR should not be merged.

[rgossiaux]

Thanks!

You need to update the peerDependencies to 3.47.0 as well, since users will need that for this to work. For that reason I haven't rushed to implementing this, so I'll probably merge your PR in a couple weeks (also gives us a little more time for bugs in svelte:element to be found).

[rgossiaux]

Oh, and yes, the TS types can be simplified now, as you mentioned--we should delete the hardcoded list of elements.

[rgossiaux]

Thanks for this PR @benjavicente ! I know I'm responding to it a little late :) I've switched over to svelte:element in the next branch (see #96) so I'm going to close this now. I like your changes to elements.ts but for some reason they make svelte-check take about 10x longer so I'm not incorporating them for now.