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_czech_czech_republic.1250.vim b/runtime/lang/menu_czech_czech_republic.1250.vim
index 9502288..6691a88 100644
--- a/runtime/lang/menu_czech_czech_republic.1250.vim
+++ b/runtime/lang/menu_czech_czech_republic.1250.vim
@@ -2,6 +2,7 @@
 " Maintainer:           Jiri Sedlak <jiri_sedlak@users.sourceforge.net>
 " Previous maintainer:  Jiri Brezina
 " Based on:             menu.vim (2012-10-21)
+" Generated from menu_cs_cz.utf-8.vim, DO NOT EDIT
 
 " Quit when menu translations have already been done.
 if exists("did_menu_trans")