Define matchers on InverseAsymmetricMatchers for expect.not

[dharkness]

The matchers are not visible in auto-completion when used with expect.not. They work, but WebStorm reports them as a problem.

const value = {
  name: 'foobar',
};
expect(value).toEqual({
  name: expect.not.toStartWith('bar')
                   ^^^^^^^^^^^
                   Unresolved function or method
});

The simplest way to expose them is by declaring the asymmetric forms in a new interface, AsymmetricMatchers, and having both Expect and InverseAsymmetricMatchers extend it. However, this may cause issues with TypeScript projects. In that case, I think we'd have to declare the matchers a third time.

Here's how I do it for my own custom matchers:

interface AsymmetricMatchers {
  ... custom matchers ...
}

interface Expect extends AsymmetricMatchers {}
interface InverseAsymmetricMatchers extends AsymmetricMatchers {}