change some doc examples to iex style
change some doc examples to iex style

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