Update doc for obsolescence of "unibyte: t"

* doc/emacs/mule.texi (Disabling Multibyte):
* doc/lispref/loading.texi (Loading Non-ASCII):
Replace the obsolete "unibyte: t" with "coding: raw-text".
* etc/NEWS: Related markup.

doc/emacs/ChangeLog

 2012-05-10  Glenn Morris  <rgm@gnu.org>
 
+	* mule.texi (Disabling Multibyte): Replace the obsolete "unibyte: t"
+	with "coding: raw-text".
+
 	* files.texi (Interlocking): Mention create-lockfiles option.
 
 2012-05-09  Chong Yidong  <cyd@gnu.org>

doc/emacs/mule.texi

@@ -287,20 +287,17 @@ auto mode selection.
 This includes the Emacs initialization
 file, @file{.emacs}, and the initialization files of packages
 such as Gnus.  However, you can specify unibyte loading for a
-particular Lisp file, by adding an entry @samp{unibyte: t} in a file
-local variables section (@pxref{File Variables}).  Then that file is
-always loaded as unibyte text.  Note that this does not represent a
-real @code{unibyte} variable, rather it just acts as an indicator
-to Emacs in the same way as @code{coding} does (@pxref{Specify Coding}).
+particular Lisp file, by adding an entry @samp{coding: raw-text} in a file
+local variables section.  @xref{Specify Coding}.
+Then that file is always loaded as unibyte text.
 @ignore
 @c I don't see the point of this statement:
 The motivation for these conventions is that it is more reliable to
 always load any particular Lisp file in the same way.
 @end ignore
-Note also that this feature only applies to @emph{loading} Lisp files
-for evaluation, not to visiting them for editing.  You can also load a
-Lisp file as unibyte, on any one occasion, by typing @kbd{C-x
-@key{RET} c raw-text @key{RET}} immediately before loading it.
+You can also load a Lisp file as unibyte, on any one occasion, by
+typing @kbd{C-x @key{RET} c raw-text @key{RET}} immediately before
+loading it.
 
 @c See http://debbugs.gnu.org/11226 for lack of unibyte tooltip.
 @vindex enable-multibyte-characters

doc/lispref/ChangeLog

 2012-05-10  Glenn Morris  <rgm@gnu.org>
 
+	* loading.texi (Loading Non-ASCII): Replace the obsolete "unibyte: t"
+	with "coding: raw-text".
+
 	* files.texi (File Locks): Mention create-lockfiles option.
 
 2012-05-09  Glenn Morris  <rgm@gnu.org>

doc/lispref/loading.texi

@@ -374,7 +374,7 @@ strings are multibyte strings should not be noticeable, since
 inserting them in unibyte buffers converts them to unibyte
 automatically.  However, if this does make a difference, you can force
 a particular Lisp file to be interpreted as unibyte by writing
-@samp{unibyte: t} in a local variables section.  With
+@samp{coding: raw-text} in a local variables section.  With
 that designator, the file will unconditionally be interpreted as
 unibyte, even in an ordinary multibyte Emacs session.  This can matter
 when making keybindings to non-@acronym{ASCII} characters written as

etc/NEWS

@@ -69,6 +69,7 @@ specifying any file to visit or expression to evaluate.
 ** You can prevent the creation of lock files by setting `create-lockfiles'
 to nil.  Use with caution, and only if you really need to.
 
++++
 ** Using "unibyte: t" in Lisp source files is obsolete.
 Use "coding: raw-text" instead.