Fix documentation of immutable.Queue
Fix documentation of immutable.Queue

`enqueue` appends elements to the `Queue`, it doesn't prepend them.
scala/scala,martijnhoekstra/scala,martijnhoekstra/scala,scala/scala,lrytz/scala,lrytz/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,shimib/scala,shimib/scala,shimib/scala,lrytz/scala,scala/scala,scala/scala,lrytz/scala,shimib/scala,scala/scala,martijnhoekstra/scala,shimib/scala,shimib/scala,lrytz/scala,martijnhoekstra/scala