maint: add coding cookies to non-ASCII sources Otherwise, Emacs might do the wrong thing if run in an he_IL.ISO-8859-8 locale, which an Emacs developer does on occasion. Problem reported by Eli Zaretskii in: http://lists.gnu.org/archive/html/emacs-devel/2015-09/msg00966.html Don't bother with test files, as they aren't copied to the Emacs source directory. If this problem affects test files in some other GNU project, we can add coding cookies to the non-ASCII test files later.