Update RST documentation for a cleaner conversion (#22895)

Our documentation conversion script got confused by some of the things found
in the rst sources

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

@@ -1,10 +1,12 @@
 package docs.camel
 
+//#imports
 import akka.actor.{ Props, ActorSystem }
 import akka.camel.CamelExtension
 
 import language.postfixOps
 import akka.util.Timeout
+//#imports
 
 object Introduction {
   def foo(): Unit = {
@@ -106,4 +108,4 @@ object Introduction {
     //#CamelDeactivation
   }
 
-}
+}