message: docs: remove deprecated `fromPromise` from RxJS guide
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diff: @@ -53,7 +53,7 @@ RxJS provides many operators, but only a handful are used frequently. For a list
  | Area | Operators |
  | :------------| :----------|
  -| Creation | `from`, `fromPromise`,`fromEvent`, `of` |
  +| Creation | `from`,`fromEvent`, `of` |
  | Combination | `combineLatest`, `concat`, `merge`, `startWith` , `withLatestFrom`, `zip` |
  | Filtering | `debounceTime`, `distinctUntilChanged`, `filter`, `take`, `takeUntil` |
  | Transformation | `bufferTime`, `concatMap`, `map`, `mergeMap`, `scan`, `switchMap` |
  