[ETCM-52] Fix scalastyle issues

Author: kapke

src/main/scala/io/iohk/ethereum/utils/Ref.scala

@@ -3,13 +3,13 @@ package io.iohk.ethereum.utils
 import java.util.concurrent.atomic.AtomicReference
 
 /**
- * An [[https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/AtomicReference.html java.util.concurrent.atomic.AtomicReference]] that can be set once.
- */
+  * An [[https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/AtomicReference.html AtomicReference]] that can be set once.
+  */
 class Ref[T <: AnyRef] {
   private[this] final val ref = new AtomicReference[Option[T]](None)
 
   // set once (but not necessarily compute once)
-  final def setOnce(t: ⇒T): Boolean = ref.get().isEmpty && ref.compareAndSet(None, Some(t))
+  final def setOnce(t: ⇒ T): Boolean = ref.get().isEmpty && ref.compareAndSet(None, Some(t))
 
   final def isDefined: Boolean = ref.get().isDefined
   final def isEmpty: Boolean = ref.get().isEmpty