Fix useErrorBoundary hook callback type (#2397)
Fix useErrorBoundary hook callback type (#2397)

Fixes TypeScript typings for useErrorBoundary to match documentation
and actual code[1], allowing to get error through the parameter of
its callback[2].

Example of previously failing code:

```
const [error] = useErrorBoundary(error => {
//                               ^~~~~~~~~~
// Argument of type '(error: any) => void' is not assignable to
// parameter of type '() => void | Promise<void>'.ts(2345)
//
	console.log(error);
});
```

[1]: https://git.io/JvrIP (/hooks/src/index.js:243:44)
[2]: https://preactjs.com/guide/v10/hooks/#useerrorboundary
developit/preact,developit/preact