bug#4554: local variable for updating the time stamp on save

[Juri Linkov <juri@jurta.org>]

The defcustom `safe-local-eval-forms' contains

    '((add-hook 'write-file-hooks 'time-stamp))

but the documentation suggests using

    (add-hook 'before-save-hook 'time-stamp)

This patch adds the recommended form to `safe-local-eval-forms' as well:

Index: lisp/files.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/files.el,v
retrieving revision 1.1083
diff -c -r1.1083 files.el
*** lisp/files.el	21 Sep 2009 22:12:30 -0000	1.1083
--- lisp/files.el	24 Sep 2009 20:47:28 -0000
***************
*** 2687,2693 ****
    :group 'find-file
    :type 'alist)
  
! (defcustom safe-local-eval-forms '((add-hook 'write-file-hooks 'time-stamp))
    "Expressions that are considered safe in an `eval:' local variable.
  Add expressions to this list if you want Emacs to evaluate them, when
  they appear in an `eval' local variable specification, without first
--- 2687,2695 ----
    :group 'find-file
    :type 'alist)
  
! (defcustom safe-local-eval-forms
!   '((add-hook 'before-save-hook 'time-stamp)
!     (add-hook 'write-file-hooks 'time-stamp))
    "Expressions that are considered safe in an `eval:' local variable.
  Add expressions to this list if you want Emacs to evaluate them, when
  they appear in an `eval' local variable specification, without first

-- 
Juri Linkov
http://www.jurta.org/emacs/