message: fix: do not reference DOM-related imports
  * fix: do not reference DOM-related imports
  Closes
  * chore: fix typo
diff: //////////////////////////////////////////////////////////
  // tslint:disable: no-reference
  -/// <reference path="./ajax/index.ts" />
  -/// <reference path="./fetch/index.ts" />
  +// It's tempting to add references to all of the deep-import locations, but
  +// adding references to those that require DOM types breaks Node projects.
  /// <reference path="./operators/index.ts" />
  /// <reference path="./testing/index.ts" />
  -/// <reference path="./webSocket/index.ts" />
  // tslint:enable: no-reference
  /* Observable */
  