Adds the contents of the final version of the Magma.Artefacts.ModuleDoc as the @moduledoc.

Usually this done via use Magma.

warning

If you decide to include your moduledocs with this macro, be aware that if you're writing a library and your users should be able to use these docs on their machines, e.g. with the h helper in IEx you'll have to include the Magma documents with the final moduledocs in your package like this:

defp package do
  [
    # ...
    files:  ~w[lib priv mix.exs docs.magma/artefacts/final/modules/**/*.md]
  ]
end