Traversable instance for DLists

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

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

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

instance Batteries.instTraversableDList : Traversable DList

instance Batteries.instLawfulTraversableDList : LawfulTraversable DList

instance Batteries.instInhabitedDList_mathlib {α : Type u_2} : Inhabited (DList α)