patch 8.2.4420: menu translations are inconsistent

Problem:    Menu translations are inconsistent.
Solution:   Add a Makefile to convert between encodings. (Ada (Haowen) Yu,
            closes #9801)
diff --git a/runtime/lang/menu_zh_tw.utf-8.vim b/runtime/lang/menu_zh_tw.utf-8.vim
index 7bef83c..693e28d 100644
--- a/runtime/lang/menu_zh_tw.utf-8.vim
+++ b/runtime/lang/menu_zh_tw.utf-8.vim
@@ -1,6 +1,7 @@
 " Menu Translations:	Traditional Chinese
 " Translated By:	Hung-Te Lin	<piaip@csie.ntu.edu.tw>
 " Last Change:		2012 May 01
+" Original translations
 
 " {{{ Quit when menu translations have already been done.
 if exists("did_menu_trans")