document channel and !!/!!! changes

akka-docs/intro/getting-started-first-java.rst

@@ -435,7 +435,7 @@ Here is the master actor::
 
 A couple of things are worth explaining further.
 
-First, we are passing in a ``java.util.concurrent.CountDownLatch`` to the ``Master`` actor. This latch is only used for plumbing (in this specific tutorial), to have a simple way of letting the outside world knowing when the master can deliver the result and shut down. In more idiomatic Akka code, as we will see in part two of this tutorial series, we would not use a latch but other abstractions and functions like ``Channel``, ``Future`` and ``?`` to achieve the same thing in a non-blocking way. But for simplicity let's stick to a ``CountDownLatch`` for now.
+First, we are passing in a ``java.util.concurrent.CountDownLatch`` to the ``Master`` actor. This latch is only used for plumbing (in this specific tutorial), to have a simple way of letting the outside world knowing when the master can deliver the result and shut down. In more idiomatic Akka code, as we will see in part two of this tutorial series, we would not use a latch but other abstractions and functions like ``Channel``, ``Future`` and ``ask()`` to achieve the same thing in a non-blocking way. But for simplicity let's stick to a ``CountDownLatch`` for now.
 
 Second, we are adding a couple of life-cycle callback methods; ``preStart`` and ``postStop``. In the ``preStart`` callback we are recording the time when the actor is started and in the ``postStop`` callback we are printing out the result (the approximation of Pi) and the time it took to calculate it. In this call we also invoke ``latch.countDown()`` to tell the outside world that we are done.