fix 2.12

Author: SethTisue

plugin/src/main/scala-2.12/com/typesafe/genjavadoc/Comments.scala

@@ -3,10 +3,10 @@ import scala.reflect.internal.util.Position
 import scala.tools.nsc.doc.ScaladocSyntaxAnalyzer
 
 trait Comments extends BaseComments { this: TransformCake =>
-  val parser = new ScaladocSyntaxAnalyzer[global.type](global) {
+  object parser extends {
     val runsAfter = List[String]()
     val runsRightAfter = None
-  }
+  } with ScaladocSyntaxAnalyzer[global.type](global)
 
   override def parseComments(): Unit =
     new parser.ScaladocUnitParser(unit, Nil) {