* ⇒, →, ←
* 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
Previously, the paths were just relative paths and depended on the working
directory of the sbt process. However, that's unreliable when the akka
sources are included in another build as in the akka-http nightlies.
