Add View Transition types

[Turbocat6413]

The problem

Previously, only the following use case was available when using the View Transition API:

document.startViewTransition(() => updateTheDOMSomehow(data));
Now all major browsers (except Firefox) support View Transition types, but Svelte doesn't provide needed typescript types

Solution

New types should be added according to the standard

const direction = determineBackwardsOrForwards();

const t = document.startViewTransition({
  update: updateTheDOMSomehow,
  types: ['slide', direction],
});

Example from Chrome for developers

Importance

Without this, it is extremely difficult to use the View Transition API in conjunction with TypeScript

[dummdidumm]

These are not types we control, those live within dom.d.ts (or similar, don't have the exact name at hand) within the Typescript package. It's on them to eventually provide them. Therefore closing.