fixes addEventListener TS declaration to return RN.EmitterSubscription

[mikemikhaylov]

Actual implementation of Tts class has method

addEventListener(type, handler) {
    return this.addListener(type, handler);
  }

which returns EmitterSubscription And the typescript declaration currently does not. Added it to be able to call remove() on it, since NativeEventEmitter.removeListener is now deprecated https://github.com/facebook/react-native/blob/main/Libraries/EventEmitter/NativeEventEmitter.js#L99

[mikemikhaylov]

Hey @ak1394 just friendly reminder

[ak1394]

Thanks!