Subtle change in Completable's documentation for retryWhen. (#4810)

Author: Shyish

src/main/java/io/reactivex/Completable.java

@@ -1398,7 +1398,7 @@ public final Completable retry(Predicate<? super Throwable> predicate) {
 
     /**
      * Returns a Completable which given a Publisher and when this Completable emits an error, delivers
-     * that error through a Flowable and the Publisher should return a value indicating a retry in response
+     * that error through a Flowable and the Publisher should signal a value indicating a retry in response
      * or a terminal event indicating a termination.
      * <dl>
      *  <dt><b>Scheduler:</b></dt>