As most Elixir projects, the docs are on hexdocs: aws-elixir v0.13.3 — Documentation - The README could make it clearer though, probably a good opportunity for a first PR. Go for it!
Given it is auto-generated, I don’t see an issue with generating both. Especially because Erlang developers do not want to bring Elixir as a dependency and Elixir developers don’t want to lose the nicely generated ExDoc documentation we have today.