[ruby/reline] Yank by em-kill-region correctly

This closes ruby/reline#106.

https://github.com/ruby/reline/commit/2549a52e15

lib/reline/line_editor.rb

@@ -1941,6 +1941,7 @@ class Reline::LineEditor
       @cursor = 0
     end
   end
+  alias_method :kill_line, :em_kill_line
 
   private def em_delete(key)
     if (not @is_multiline and @line.empty?) or (@is_multiline and @line.empty? and @buffer_of_lines.size == 1)
@@ -2139,9 +2140,10 @@ class Reline::LineEditor
       @byte_pointer -= byte_size
       @cursor -= width
       @cursor_max -= width
-      @kill_ring.append(deleted)
+      @kill_ring.append(deleted, true)
     end
   end
+  alias_method :unix_word_rubout, :em_kill_region
 
   private def copy_for_vi(text)
     if @config.editing_mode_is?(:vi_insert) or @config.editing_mode_is?(:vi_command)

test/reline/test_key_actor_emacs.rb

@@ -2185,6 +2185,24 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     assert_line('hoge')
   end
 
+  def test_em_kill_region_with_kill_ring
+    input_keys("def hoge\C-b\C-b\C-b\C-b", false)
+    assert_byte_pointer_size('def ')
+    assert_cursor(4)
+    assert_cursor_max(8)
+    assert_line('def hoge')
+    input_keys("\C-k\C-w", false)
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    assert_line('')
+    input_keys("\C-y", false)
+    assert_byte_pointer_size('def hoge')
+    assert_cursor(8)
+    assert_cursor_max(8)
+    assert_line('def hoge')
+  end
+
 =begin # TODO: move KeyStroke instance from Reline to LineEditor
   def test_key_delete
     input_keys('ab')