Add marble diagrams to the Single.delay method (#6076)

* Add marble diagrams to the Single.delay method

* Update marbles for Single.delay with error events

* Use correct marble diagram URLs for Single.delay methods

Author: UMFsimke

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

@@ -1980,6 +1980,8 @@ public final Flowable<T> concatWith(SingleSource<? extends T> other) {
     /**
      * Delays the emission of the success signal from the current Single by the specified amount.
      * An error signal will not be delayed.
+     * <p>
+     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.delay.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -1998,6 +2000,8 @@ public final Single<T> delay(long time, TimeUnit unit) {
 
     /**
      * Delays the emission of the success or error signal from the current Single by the specified amount.
+     * <p>
+     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.delay.e.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>{@code delay} operates by default on the {@code computation} {@link Scheduler}.</dd>
@@ -2019,6 +2023,8 @@ public final Single<T> delay(long time, TimeUnit unit, boolean delayError) {
     /**
      * Delays the emission of the success signal from the current Single by the specified amount.
      * An error signal will not be delayed.
+     * <p>
+     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.delay.s.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>you specify the {@link Scheduler} where the non-blocking wait and emission happens</dd>
@@ -2041,6 +2047,8 @@ public final Single<T> delay(final long time, final TimeUnit unit, final Schedul
 
     /**
      * Delays the emission of the success or error signal from the current Single by the specified amount.
+     * <p>
+     * <img width="640" height="457" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Single.delay.se.png" alt="">
      * <dl>
      * <dt><b>Scheduler:</b></dt>
      * <dd>you specify the {@link Scheduler} where the non-blocking wait and emission happens</dd>