title: @groupname tag is not working with a scala class in intellij
body: <p>@groupname tags are not getting identified in the documentation for Scala. I am using Intellij IDE for creating the Scala doc.</p>
  
  <p>Using @groupname tag on Scala objects seem to work fine but with class, I ma only finding value members not arranged in groups.</p>
  
  <pre><code>/**
    * A class to represent ''All Methods needed for Stdraw Tests''.
    * @groupname some_funcs Some Functions
    * @constructor Create Some Functions
  */
  class xyz{
   /**
    * @group some_funcs
    */
  def something() = {something}
  }
  </code></pre>
  
  <p>When I run this code with Generate Scala doc, i should get something function with heading Some Functions, but I get nothing. I see only the valued members. Even tried adding "scalacOptions in (Compile,doc) := Seq("-groups", "-implicits")" in build.sbt which did nothing. Any one faced this issue.</p>