message: docs(concat): improve short description
diff: @@ -21,7 +21,7 @@ export function concat<A extends ObservableInput<any>[]>(...observables: A): Obs
  /* tslint:enable:max-line-length */
  /**
  - * Creates an output Observable which sequentially emits all values from given
  + * Creates an output Observable which sequentially emits all values from the first given
  * Observable and then moves on to the next.
  *
  * <span class="informal">Concatenates multiple Observables together by
  