fix(types): improve `e.detail` type for dispatched events

[metonym]

Some dispatched events do not have an explicit type annotation, and thus default to CustomEvent<any>.

This PR enhances the DX by explicitly annotating the type.

<Slider
  on:change="{(e) => {
    console.log(e.detail); // number
  }}"
/>

[metonym]

Fixed in v0.82.9