Traversable instance for DLists

This file provides the equivalence between List α and DList α and the traversable instance for DList.

def Std.DList.listEquivDList (α : Type u_1) : List α ≃ Std.DList α

The natural equivalence between lists and difference lists, using DList.ofList and DList.toList.

instance Std.instTraversableDList : Traversable Std.DList

instance Std.instLawfulTraversableDListInstTraversableDList : LawfulTraversable Std.DList

instance Std.instInhabitedDList {α : Type u_2} : Inhabited (Std.DList α)