1.x: alias Observable.doOnCompleted to match Completable and 2x

Closes #3700.

Author: zach-klippenstein

src/main/java/rx/Observable.java

@@ -4453,12 +4453,31 @@ public final <U> Observable<T> distinctUntilChanged(Func1<? super T, ? extends U
      *            the action to invoke when the source Observable calls {@code onCompleted}
      * @return the source Observable with the side-effecting behavior applied
      * @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
+     * @deprecated use {@link #doOnComplete(Action0)} instead.
      */
-    public final Observable<T> doOnCompleted(final Action0 onCompleted) {
+    @Deprecated public final Observable<T> doOnCompleted(final Action0 onCompleted) {
+        return doOnComplete(onCompleted);
+    }
+
+    /**
+     * Modifies the source Observable so that it invokes an action when it calls {@code onCompleted}.
+     * <p>
+     * <img width="640" height="305" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/doOnCompleted.png" alt="">
+     * <dl>
+     *  <dt><b>Scheduler:</b></dt>
+     *  <dd>{@code doOnComplete} does not operate by default on a particular {@link Scheduler}.</dd>
+     * </dl>
+     *
+     * @param onComplete
+     *            the action to invoke when the source Observable calls {@code onCompleted}
+     * @return the source Observable with the side-effecting behavior applied
+     * @see <a href="http://reactivex.io/documentation/operators/do.html">ReactiveX operators documentation: Do</a>
+     */
+    public final Observable<T> doOnComplete(final Action0 onComplete) {
         Observer<T> observer = new Observer<T>() {
             @Override
             public final void onCompleted() {
-                onCompleted.call();
+                onComplete.call();
             }
 
             @Override