Add marble diagram for Single.hide operator (#6077)

* Add marble diagram for Single.hide operator

* Use correct marble diagram URL for Single.hide method

Author: UMFsimke

src/main/java/io/reactivex/Single.java

@@ -1877,6 +1877,8 @@ public final <R> R as(@NonNull SingleConverter<T, ? extends R> converter) {
     /**
      * Hides the identity of the current Single, including the Disposable that is sent
      * to the downstream via {@code onSubscribe()}.
+     * <p>
+     * <img width="640" height="458" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.hide.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code hide} does not operate by default on a particular {@link Scheduler}.</dd>