Remove note about length limitation in in/2 (#10960)
Remove note about length limitation in in/2 (#10960)

Such limitation was removed in 4a2047af1fda32f814e6b9a07b5aa5acd59e1d6b
kimshrier/elixir,joshprice/elixir,pedrosnk/elixir,michalmuskala/elixir,kelvinst/elixir,elixir-lang/elixir,kimshrier/elixir,kelvinst/elixir,pedrosnk/elixir