Fix javadoc on RxJavaHooks.setOnError (#4257)

Author: davidmoten

src/main/java/rx/plugins/RxJavaHooks.java

@@ -580,7 +580,7 @@ public static <T, R> Completable.CompletableOperator onCompletableLift(Completab
      * <p>
      * This operation is threadsafe.
      * <p>
-     * Calling with a {@code null} parameter restores the default behavior:
+     * Calling with a {@code null} parameter has the effect that
      * errors are routed to the current thread's {@link UncaughtExceptionHandler}.
      * @param onError the action that will receive undeliverable Throwables
      */