=act #3572 Add parens to sender

* because it is not referentially transparent; normally we reserved parens for
  side-effecting code but given how people thoughtlessly close over it we revised
  that that decision for sender
* caller can still omit parens

akka-docs/rst/scala/code/docs/camel/Consumers.scala

@@ -28,7 +28,7 @@ object Consumers {
       def endpointUri = "jetty:http://localhost:8877/camel/default"
 
       def receive = {
-        case msg: CamelMessage => sender ! ("Hello %s" format msg.bodyAs[String])
+        case msg: CamelMessage => sender() ! ("Hello %s" format msg.bodyAs[String])
       }
     }
     //#Consumer2
@@ -46,12 +46,12 @@ object Consumers {
 
       def receive = {
         case msg: CamelMessage =>
-          sender ! Ack
+          sender() ! Ack
           // on success
           // ..
           val someException = new Exception("e1")
           // on failure
-          sender ! Failure(someException)
+          sender() ! Failure(someException)
       }
     }
     //#Consumer3
@@ -65,7 +65,7 @@ object Consumers {
       def endpointUri = "jetty:http://localhost:8877/camel/default"
       override def replyTimeout = 500 millis
       def receive = {
-        case msg: CamelMessage => sender ! ("Hello %s" format msg.bodyAs[String])
+        case msg: CamelMessage => sender() ! ("Hello %s" format msg.bodyAs[String])
       }
     }
     //#Consumer4

akka-docs/rst/scala/code/docs/camel/CustomRoute.scala

@@ -19,7 +19,7 @@ object CustomRoute {
     class Responder extends Actor {
       def receive = {
         case msg: CamelMessage =>
-          sender ! (msg.mapBody {
+          sender() ! (msg.mapBody {
             body: String => "received %s" format body
           })
       }
@@ -53,7 +53,7 @@ object CustomRoute {
         handled(true).transform(Builder.exceptionMessage).end
 
       final override def preRestart(reason: Throwable, message: Option[Any]) {
-        sender ! Failure(reason)
+        sender() ! Failure(reason)
       }
     }
     //#ErrorThrowingConsumer

akka-docs/rst/scala/code/docs/camel/Producers.scala

@@ -120,7 +120,7 @@ object Producers {
       def receive = {
         case msg =>
           val template = CamelExtension(context.system).template
-          sender ! template.requestBody("direct:news", msg)
+          sender() ! template.requestBody("direct:news", msg)
       }
     }
     //#RequestProducerTemplate

akka-docs/rst/scala/code/docs/camel/PublishSubscribe.scala

@@ -27,7 +27,7 @@ object PublishSubscribe {
     def receive = {
       case msg: CamelMessage => {
         publisher ! msg.bodyAs[String]
-        sender ! ("message published")
+        sender() ! ("message published")
       }
     }
   }