anchor.diff:  This injects a reference to the parent command of the mixee into the mixin.
   Here is an example implementation:
   
  -[source,java]
  +.Java
  +[source,java,role="primary"]
   ----
   // Define a mixin that delegates to the parent command.
   class MyMixin {
  
positive.code: This can be useful when a mixin contains logic that is common to many commands.
  For example:
  
  [source,java]
  ----
  class AdvancedMixin {
      @Spec(Spec.Target.MIXEE) CommandSpec mixee;
  
negative.code: }
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  class MyApp : Runnable {
  
      @Mixin
      lateinit var myLogger: MyLogger
  
      override fun run() {
          myLogger.info("Hello info%n")
          myLogger.debug("Hello debug%n")
          myLogger.trace("Hello trace%n")
      }
  
      companion object {
          @JvmStatic
          fun main(args: Array<String>) {
              exitProcess(CommandLine(MyApp()).execute(*args))
          }
      }
  }
  ----
  
  ==== Accessing the Mixee from a Mixin
  
  Sometimes you need to write a Mixin class that accesses the mixee (the command where it is mixed in).
  