=doc #3986 Slight updates in wording on cluster singleton docs
=sam Update version numbers to 2.4-SNAPSHOT
=sam #15028 Change reference from java file to scala file
Merge pull request #15029 from kpfell/15028-akka-sample-cluster-scala-tutorial-fix

=sam #15028 Change reference from java file to scala file
Merge pull request #15008 from ktoso/3986-cluster-singleton-may-become-doubleton-during-splits-ktoso

=doc #3986 Slight updates in wording on cluster singleton docs
Merge pull request #15019 from akka/wip-update-sample-version-numbers-ban

=sam Update version numbers to 2.4-SNAPSHOT
=pro use sbt-unidoc plugin