(buffer-stale-function): Add hyperlink to emacs-xtra manual to docstring.

diff --git a/lisp/files.el b/lisp/files.el
index dc84c79df8408b37b914a6721bbe32d28177a7de..2b038c8e9c64e1f08deb27840e6733eed9f27a6a 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -3480,7 +3480,10 @@ this function is called.
 The idea behind the NOCONFIRM argument is that it should be
 non-nil if the buffer is going to be reverted without asking the
 user.  In such situations, one has to be careful with potentially
-time consuming operations.")
+time consuming operations.
+
+For more information on how this variable is used by Auto Revert mode,
+see Info node `(emacs-xtra)Supporting additional buffers'.")
 
 (defvar before-revert-hook nil
   "Normal hook for `revert-buffer' to run before reverting.