Clarify use cases around at_exit/1
Clarify use cases around at_exit/1

pedrosnk/elixir,michalmuskala/elixir,ggcampinho/elixir,ggcampinho/elixir,kelvinst/elixir,elixir-lang/elixir,joshprice/elixir,kimshrier/elixir,kimshrier/elixir,pedrosnk/elixir,kelvinst/elixir