fix: change RemoveIndexSignature to OmitIndexSignature

[Haberkamp]

The issue

The type-fest package, no longer has a RemoveIndexSignature type.

The solution

I renamed the RemoveIndexSignature import to OmitIndexSignature.

Additional

This also solves a bug when using the values of a scoped slots in the renderMethod.

render(MyComponent, {
  slots: {
    mySlot: (props) => 'Hello, world' // The `props` parameter had the type of any, this is now fixed and has the correct type 
  }
});