Include2
      module 
       X
      
       : sig ... 
       end
      
     
    Comment about X that should not appear when including X below.
       include 
        module type
         of struct
         include X
         end
       
      
     
      module 
       Y
      
       : sig ... 
       end
      
     
    Top-comment of Y.
      module 
       Y_include_synopsis
      
       : sig ... 
       end
      
     
    The include Y below should have the synopsis from
       Y's top-comment attached to it.
     
      module 
       Y_include_doc
      
       : sig ... 
       end