Trim trailing whitespace on heredocs with \r\n

Author: josevalim

Diff for: lib/elixir/lib/code/formatter.ex

@@ -1683,6 +1683,7 @@ defmodule Code.Formatter do
   end
 
   defp heredoc_line(["", _ | _]), do: nest(line(), :reset)
+  defp heredoc_line(["\r", _ | _]), do: nest(line(), :reset)
   defp heredoc_line(_), do: line()
 
   defp args_to_algebra_with_comments(args, meta, skip_parens?, last_arg_mode, join, state, fun) do

Diff for: lib/elixir/test/elixir/code_formatter/literals_test.exs

@@ -384,6 +384,14 @@ defmodule Code.Formatter.LiteralsTest do
       """
       '''
     end
+
+    test "with new lines" do
+      assert_format ~s|foo do\n  """\n  foo\n  \n  bar\n  """\nend|,
+                    ~s|foo do\n  """\n  foo\n\n  bar\n  """\nend|
+
+      assert_format ~s|foo do\r\n  """\r\n  foo\r\n  \r\n  bar\r\n  """\r\nend|,
+                    ~s|foo do\n  """\n  foo\r\n\r\n  bar\r\n  """\nend|
+    end
   end
 
   describe "charlist heredocs" do