replace unicode arrows

* ⇒, →, ←
* because we don't want to show them in documentation snippets and
  then it's complicated to avoid that when snippets are
  located in src/test/scala in individual modules
* dont replace object `→` in FSM.scala and PersistentFSM.scala

akka-cluster/src/multi-jvm/scala/akka/cluster/RestartNode2Spec.scala

@@ -77,7 +77,7 @@ abstract class RestartNode2SpecSpec
       runOn(seed2) {
         system.actorOf(Props(new Actor {
           def receive = {
-            case a: Address ⇒
+            case a: Address =>
               seedNode1Address = a
               sender() ! "ok"
           }
@@ -88,7 +88,7 @@ abstract class RestartNode2SpecSpec
       runOn(seed1) {
         enterBarrier("seed1-address-receiver-ready")
         seedNode1Address = Cluster(seed1System).selfAddress
-        List(seed2) foreach { r ⇒
+        List(seed2) foreach { r =>
           system.actorSelection(RootActorPath(r) / "user" / "address-receiver") ! seedNode1Address
           expectMsg(5.seconds, "ok")
         }