message: fix(typings): the return type of factory of defer should be ObservableInput<T>
diff: -import { Observable, SubscribableOrPromise } from '../Observable';
  +import { Observable, ObservableInput } from '../Observable';
  import { Subscriber } from '../Subscriber';
  import { Subscription } from '../Subscription';
  @@ -47,7 +47,7 @@ export class DeferObservable<T> extends Observable<T> {
  *
  * @see {@link create}
  *
  - * @param {function(): SubscribableOrPromise} observableFactory The Observable
  + * @param {function(): ObservableInput} observableFactory The Observable
  * factory function to invoke for each Observer that subscribes to the output
  * Observable. May also return a Promise, which will be converted on the fly
  * to an Observable.
  @@ -57,11 +57,11 @@ export class DeferObservable<T> extends Observable<T> {
  * @name defer
  * @owner Observable
  */
  - static create<T>(observableFactory: () => SubscribableOrPromise<T> | void): Observable<T> {
  + static create<T>(observableFactory: () => ObservableInput<T> | void): Observable<T> {
  return new DeferObservable(observableFactory);
  }
  - constructor(private observableFactory: () => SubscribableOrPromise<T> | void) {
  + constructor(private observableFactory: () => ObservableInput<T> | void) {
  super();
  }
  @@ -72,7 +72,7 @@ export class DeferObservable<T> extends Observable<T> {
  class DeferSubscriber<T> extends OuterSubscriber<T, T> {
  constructor(destination: Subscriber<T>,
  - private factory: () => SubscribableOrPromise<T> | void) {
  + private factory: () => ObservableInput<T> | void) {
  super(destination);
  this.tryDefer();
  }
  