Backport commit 25166a91 from Emacs master branch.

doc/org.texi

@@ -1,4 +1,4 @@
-\input texinfo
+\input texinfo  @c -*- coding: utf-8 -*-
 @c %**start of header
 @setfilename ../../info/org
 @settitle The Org Manual

lisp/ox-ascii.el

@@ -1965,7 +1965,7 @@ Return output file name."
 
 ;; Local variables:
 ;; generated-autoload-file: "org-loaddefs.el"
-;; coding: utf-8-emacs
+;; coding: utf-8
 ;; End:
 
 ;;; ox-ascii.el ends here