Resolves issue with autocompletion on structs not working in IEx (#5133)

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: pareeohnos

lib/iex/lib/iex/autocomplete.ex

@@ -59,9 +59,12 @@ defmodule IEx.Autocomplete do
   defp reduce(expr) do
     Enum.reduce(' ([{', expr, fn token, acc ->
       hd(:string.tokens(acc, [token]))
-    end) |> Enum.reverse |> strip_ampersand
+    end) |> Enum.reverse |> strip_ampersand |> strip_percent
   end
 
+  defp strip_percent([?% | t]), do: t
+  defp strip_percent(expr), do: expr
+
   defp strip_ampersand([?& | t]), do: t
   defp strip_ampersand(expr), do: expr
 

lib/iex/test/iex/autocomplete_test.exs

@@ -179,4 +179,13 @@ defmodule IEx.AutocompleteTest do
     :code.purge(Sample)
     :code.delete(Sample)
   end
+
+
+  defmodule MyStruct do
+    defstruct my_val: "val"
+  end
+
+  test "completion for structs" do
+    assert expand('%IEx.AutocompleteTest.MyStr') == {:yes, 'uct', []}
+  end
 end