ex_unit extractor does not work with ExUnit.CaseTemplate modules

[brosquinha]

Hi, apparently, after #480, Expert no longer detects describe/test blocks on its outline tree when using ExUnit.CaseTemplate instead of direct ExUnit.Case.

I've setup a simple reproducible project to demonstrate this issue:

1. Run mix new test_app --sup (I'm using elixir 1.19.5 and erlang 28.4 here);
2. Create the following file on lib/my_case.ex (taken directly from ExUnit documentation):

defmodule MyCase do
  use ExUnit.CaseTemplate

  using do
    quote do
      # This code is injected into every case that calls "use MyCase"
      alias TestApp
    end
  end
end

3. Apply the following diff on test/test_app_test.exs:

defmodule TestAppTest do
- use ExUnit.Case
+ use MyCase
  doctest TestApp

  test "greets the world" do
    assert TestApp.hello() == :world
  end
end

I'm also attaching this generated project here:

new-elixir.tar.gz

I personally rely on this LSP capability to quickly navigate on tests files, and since many production applications use CaseTemplate, this is a big issue for my usage.