Add constraints to type parameters of `Has`

Because typescript doesn't support strict version of Extract for union types. (https://github.com/microsoft/TypeScript/issues/31474)

How about add constraints to type parameters of `Has`?

current behavior

```ts
assert>(true); // true.
assert>(true); // also true. Can 'a' has 'a' | 'b' ?

assert>(true); // true.
assert>(true); // also true. Can `number` has `string` | `number` ?
```

Suggestion

```ts
/**
* Checks if type `T` has the specified type `U`.
*/
export declare type Has = IsAny extends true ? true : IsAny extends true ? false : Extract extends never ? false : true;
```

```ts
assert>(true); // true.
assert>(true); // Type '"a" | "b"' does not satisfy the constraint '"a"'.

assert>(true); // true.
assert>(true); // Type 'string | number' does not satisfy the constraint 'number'
```