Fix Elixir root module completion

Fixes #230

lib/elixir_sense/providers/suggestion/complete.ex

@@ -542,14 +542,19 @@ defmodule ElixirSense.Providers.Suggestion.Complete do
     depth = length(String.split(name, ".")) + 1
     base = name <> "." <> hint
 
+    concat_module = fn
+      ["Elixir", "Elixir" | _] = parts -> parts |> tl() |> Module.concat()
+      parts -> Module.concat(parts)
+    end
+
     for mod <- match_modules(base, module === Elixir, env),
         mod_as_atom = mod |> String.to_atom(),
         filter.(mod_as_atom),
         parts = String.split(mod, "."),
         depth <= length(parts),
         name = Enum.at(parts, depth - 1),
         valid_alias_piece?("." <> name),
-        concatted = parts |> Enum.take(depth) |> Module.concat(),
+        concatted = parts |> Enum.take(depth) |> concat_module.(),
         filter.(concatted) do
       {name, concatted, false}
     end

test/elixir_sense/providers/suggestion/complete_test.exs

@@ -71,7 +71,7 @@ defmodule ElixirSense.Providers.Suggestion.CompleteTest do
 
   test "elixir proxy" do
     list = expand(~c"E")
-    assert list |> Enum.find(&(&1.name == "Elixir" and &1.full_name == "Elixir.Elixir"))
+    assert list |> Enum.find(&(&1.name == "Elixir" and &1.full_name == "Elixir"))
   end
 
   test "elixir completion" do

test/elixir_sense/suggestions_test.exs

@@ -1976,7 +1976,7 @@ defmodule ElixirSense.SuggestionsTest do
     assert %{
              type: :module,
              name: "Elixir",
-             full_name: "Elixir.Elixir",
+             full_name: "Elixir",
              subtype: nil,
              summary: "",
              metadata: %{}