interface stubbing for anonymous implementations

[tvald]

Similar to #7073, provide a code action to create stubs for an anonymous implementation of a type:

interface Foo {
  field: string,
  func(): void
}

const bar: Foo = {}
// expand above line into...
const bar: Foo = {
  field: 'string',
  func(): void {
    throw new Error('not yet implemented')
  },
}

Ideally, this would also be able to stub in the anonymous implementation of a function argument, but that would require inference of the interface being targeted for implementation:

function example(arg: Foo): void { }

example({})
// expand above line into...
example({
  field: string,
  func(): void {
    throw new Error('not yet implemented')
  },
}

[mjbvz]

This issue was moved to microsoft/TypeScript#16755