Doc updates for buffer-stale-function now applying to file buffers too

* doc/emacs/arevert-xtra.texi (Supporting additional buffers):
* doc/lispref/backups.texi (Reverting):
Update for buffer-stale-function also applying to file-buffers.

* lisp/autorevert.el (auto-revert-buffers):
* lisp/files.el (buffer-stale--default-function)
(buffer-stale-function, revert-buffer--default): Doc tweaks.

* etc/NEWS: Related edits.

1 files changed, 3 insertions, 3 deletions

diff --git a/doc/emacs/arevert-xtra.texi b/doc/emacs/arevert-xtra.texi
index 0f05d1db0e..dcb73bc96d 100644
--- a/doc/emacs/arevert-xtra.texi
+++ b/doc/emacs/arevert-xtra.texi
@@ -107,11 +107,11 @@ To support auto-reverting the buffer must first of all have a suitable
 @code{revert-buffer-function}.  @xref{Definition of
 revert-buffer-function,, Reverting, elisp, the Emacs Lisp Reference Manual}.
 
-In addition, it must have a @code{buffer-stale-function}.
+In addition, it must have a suitable @code{buffer-stale-function}.
 
 @c FIXME only defvar in all of doc/emacs!
 @defvar buffer-stale-function
-The value of this variable is a function to check whether a non-file
+The value of this variable is a function to check whether a
 buffer needs reverting.  This should be a function with one optional
 argument @var{noconfirm}.  The function should return non-@code{nil}
 if the buffer should be reverted.  The buffer is current when this
@@ -132,7 +132,7 @@ If you just want to automatically auto-revert every
 @code{auto-revert-interval} seconds (like the Buffer Menu), use:
 
 @example
-(set (make-local-variable 'buffer-stale-function)
+(setq-local buffer-stale-function
      #'(lambda (&optional noconfirm) 'fast))
 @end example