Add typespecs for Enum
Add typespecs for Enum

Also fixes some documentation mistakes

ggcampinho/elixir,antipax/elixir,pedrosnk/elixir,kelvinst/elixir,gfvcastro/elixir,pedrosnk/elixir,michalmuskala/elixir,joshprice/elixir,beedub/elixir,antipax/elixir,elixir-lang/elixir,kelvinst/elixir,lexmag/elixir,gfvcastro/elixir,lexmag/elixir,kimshrier/elixir,kimshrier/elixir,beedub/elixir,ggcampinho/elixir