Tuple.append/2 is deprecated. Use insert_at instead

I started learning Elixir this week and I'm going through the koans. I got a warning on the following koan at 05_tuples.ex:

koan "Add things at the end" do
  assert Tuple.append({"Huey", "Dewey"}, "Louie") == {"Huey", "Dewey", "Louie"}
end

Apparently, Tuple.append has been deprecated since Elixir v1.18.0.

On Elixir's documentation (at https://hexdocs.pm/elixir/Tuple.html) they say the following:

"To append to a tuple, it is preferable to extract the elements from the old tuple with pattern matching, and then create a new tuple"

Since I'm new to Elixir, I don't know how to do that yet. But if anyone has the time to explain it to me, I'll gladly open a PR with the change.

[iamvery]

Thank you for reporting! What they mean is that this example would change from:

  assert Tuple.append({"Huey", "Dewey"}, "Louie") == {"Huey", "Dewey", "Louie"}

to something like

{first, second} = {"Huey", "Dewey"}
extended = {first, second, "Louie"}
assert extended == {"Huey", "Dewey", "Louie"}

We should fix the deprecation warning, and to be honest I think it makes the most sense either remove this koan or adjust its purpose to illustrate that "extending" a Tuple is just creating a new Tuple.

[iamvery]

This is fixed in #299