Further lemmas on WithTerminal

These lemmas and instances need more imports.

instance CategoryTheory.WithTerminal.instIsCofilteredOfIsCofilteredOrEmpty {C : Type u_1} [Category.{v_1, u_1} C] [IsCofilteredOrEmpty C] : IsCofiltered (WithTerminal C)

instance CategoryTheory.WithInitial.instIsFilteredOfIsFilteredOrEmpty {C : Type u_1} [Category.{v_1, u_1} C] [IsFilteredOrEmpty C] : IsFiltered (WithInitial C)