Fix Javadoc for Maybe.toSingle (#5343)

Author: paulblessing

src/main/java/io/reactivex/Maybe.java

@@ -3116,7 +3116,8 @@ public final Observable<T> toObservable() {
 
     /**
      * Converts this Maybe into a Single instance composing cancellation
-     * through and turning an empty Maybe into a signal of NoSuchElementException.
+     * through and turning an empty Maybe into a Single that emits the given
+     * value through onSuccess.
      * <dl>
      *  <dt><b>Scheduler:</b></dt>
      *  <dd>{@code toSingle} does not operate by default on a particular {@link Scheduler}.</dd>