Update documentation how to use LoadingBarService

[lopatnov]

I see comment in code:

    /** @deprecated use `useRef` instead. */
    complete(): void;
    /** @deprecated use `useRef` instead. */
    stop(): void;
   useRef(id?: string): LoadingBarState;

If stop and complete is deprecated, provide please documentation how to use useRef? What id should be as argument? And how to stop it?

[aitboudad]

const progress = useRef();
...

progress.stop();
progress. complete();