Minor doc changes in Collectable protocol moduledoc (#8543)
Minor doc changes in Collectable protocol moduledoc (#8543)

In the example, add the type the protocol is implemented for (`MapSet`).
pedrosnk/elixir,pedrosnk/elixir,lexmag/elixir,kelvinst/elixir,elixir-lang/elixir,ggcampinho/elixir,michalmuskala/elixir,kimshrier/elixir,ggcampinho/elixir,kelvinst/elixir,joshprice/elixir,lexmag/elixir,kimshrier/elixir