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.

3 files changed, 16 insertions, 4 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c35be3ec270..f6340047e0a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2014-04-04  Glenn Morris  <rgm@gnu.org>
+
+        * files.el (buffer-stale--default-function)
+        (buffer-stale-function, revert-buffer--default):
+        * autorevert.el (auto-revert-buffers): Doc tweaks.
+
 2014-04-03  Eli Zaretskii  <eliz@gnu.org>
 
         * international/characters.el: Preload uni-mirrored.el.  (Bug#17169)
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index a08bf7fee6a..f1074e22e51 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -672,7 +672,7 @@ Should `auto-revert-mode' be active in some buffers, those buffers
 are checked.
 
 Non-file buffers that have a custom `revert-buffer-function' and
-a `buffer-stale-function' are reverted either when Auto-Revert
+`buffer-stale-function' are reverted either when Auto-Revert
 Mode is active in that buffer, or when the variable
 `global-auto-revert-non-file-buffers' is non-nil and Global
 Auto-Revert Mode is active.
diff --git a/lisp/files.el b/lisp/files.el
index d5c6028ff47..e721a813a59 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -5349,13 +5349,16 @@ This should not be relied upon.")
   "Default function to use for `buffer-stale-function'.
 This function ignores its argument.
 This returns non-nil if the current buffer is visiting a readable file
-whose modification time does not match that of the buffer."
+whose modification time does not match that of the buffer.
+
+This function only handles buffers that are visiting files.
+Non-file buffers need a custom function"
   (and buffer-file-name
        (file-readable-p buffer-file-name)
        (not (verify-visited-file-modtime (current-buffer)))))
 
 (defvar buffer-stale-function #'buffer-stale--default-function
-  "Function to check whether a non-file buffer needs reverting.
+  "Function to check whether a buffer needs reverting.
 This should be a function with one optional argument NOCONFIRM.
 Auto Revert Mode passes t for NOCONFIRM.  The function should return
 non-nil if the buffer should be reverted.  A return value of
@@ -5450,7 +5453,10 @@ start and end.
 
 Calls `revert-buffer-insert-file-contents-function' to reread the
 contents of the visited file, with two arguments: the first is the file
-name, the second is non-nil if reading an auto-save file."
+name, the second is non-nil if reading an auto-save file.
+
+This function only handles buffers that are visiting files.
+Non-file buffers need a custom function."
   (with-current-buffer (or (buffer-base-buffer (current-buffer))
                            (current-buffer))
     (let* ((auto-save-p (and (not ignore-auto)