Fix typo in files.texi

doc/lispref/ChangeLog

+2012-09-25  Leo Liu  <sdl.web@gmail.com>
+
+	* files.texi (Files): Fix typo.
+
 2012-09-12  Glenn Morris  <rgm@gnu.org>
 
 	* debugging.texi (Using Debugger): Fix typo.

doc/lispref/files.texi

@@ -31,7 +31,7 @@ arguments, except where noted.  @xref{Magic File Names}, for details.
   When file I/O functions signal Lisp errors, they usually use the
 condition @code{file-error} (@pxref{Handling Errors}).  The error
 message is in most cases obtained from the operating system, according
-to locale @code{system-message-locale}, and decoded using coding system
+to locale @code{system-messages-locale}, and decoded using coding system
 @code{locale-coding-system} (@pxref{Locales}).
 
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