Clarify documentation for Task.async_stream/5

[Dalgona]

Environment

• Elixir & Erlang versions (elixir -v):

  Erlang/OTP 18 [erts-7.3] [source] [64-bit] [async-threads:10] [hipe] [kernel-poll:false]
  
  Elixir 1.4.0
  

• Operating system:

  Debian GNU/Linux 8.5 (jessie)

Current behavior

The documentation for Task.async_stream/5 says:

tasks.ex:288:
Each item will be appended to the given args and processed by its own task.

And I simply guessed each item in the enumerable will be appended so that the item becomes the last item of args. But when I actually tried this function, I saw the item had been passed as the first argument to the given function, and it makes me a little bit confused.

Expected behavior

I am quite new to functional programming languages, and the word "appending" may have different meaning in this world. But whether it's intended or not, I think this still needs to be clarified by using the opposite word, or by adding some additional explanation.

[josevalim]

Oops, the documentation is wrong. Such a small but confusing mistake. I will fix it in master and v1.4, thank you for reporting! ❤️

[Dalgona]

Thank you!