Add a section about iodata to the IO docs (#8943)
Add a section about iodata to the IO docs (#8943)

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