correctly encode output messages as binary

Fixes elixir-lsp/vscode-elixir-ls#322
Bug introduced in #457

Author: lukaszsamson

apps/elixir_ls_utils/lib/output_device.ex

@@ -2,15 +2,9 @@ defmodule ElixirLS.Utils.OutputDevice do
   @moduledoc """
   Intercepts IO request messages and forwards them to the Output server to be sent as events to
   the IDE. Implements [Erlang I/O Protocol](https://erlang.org/doc/apps/stdlib/io_protocol.html)
-
-  In order to send console output to Visual Studio Code, the debug adapter needs to send events
-  using the usual wire protocol. In order to intercept the debugged code's output, we replace the
-  registered processes `:user` and `:standard_error` and the process's group leader with instances
-  of this server. When it receives a message containing output, it sends an event via the `Output`
-  server with the correct category ("stdout" or "stderr").
   """
 
-  @opts binary: true, encoding: :unicode
+  @opts binary: true, encoding: :latin1
 
   ## Client API
 

apps/elixir_ls_utils/test/output_device_test.exs

@@ -284,7 +284,7 @@ defmodule ElixirLS.Utils.OutputDeviceTest do
       output_device: output_device
     } do
       send(output_device, {:io_request, self(), 123, :getopts})
-      assert_receive({:io_reply, 123, [binary: true, encoding: :unicode]})
+      assert_receive({:io_reply, 123, [binary: true, encoding: :latin1]})
     end
 
     test "valid can be set", %{