Revert "IEx autocompletion should show all exported functions, not only documented ones"

This reverts commit 3ffc5e9.

Closes #879.

Author: José Valim

lib/iex/lib/iex/autocomplete.ex

@@ -253,7 +253,11 @@ defmodule IEx.Autocomplete do
 
   defp get_funs(mod) do
     if function_exported?(mod, :__info__, 1) do
-      (mod.__info__(:functions) -- [__info__: 1]) ++ mod.__info__(:macros)
+      if docs = mod.__info__(:docs) do
+        lc { tuple, _line, _kind, _sign, doc } inlist docs, doc != false, do: tuple
+      else
+        (mod.__info__(:functions) -- [__info__: 1]) ++ mod.__info__(:macros)
+      end
     else
       mod.module_info(:exports)
     end

lib/iex/test/iex/autocomplete_test.exs

@@ -54,11 +54,6 @@ defmodule IEx.AutocompleteTest do
     assert expand('System.ve') == {:yes, 'rsion', []}
   end
 
-  test :elixir_function_nodoc do
-    {:yes, '', list} = expand('Keyword.get')
-    assert 'get/2' inlist list
-  end
-
   test :elixir_function_completion_with_arity do
     assert expand('String.printable?')  == {:yes, '', ['printable?/1']}
     assert expand('String.printable?/') == {:yes, '', ['printable?/1']}