Fix midnight-mode documentation

* lisp/midnight.el (Commentary): Document that 'midnight-mode' should be
enabled using the function, instead of by merely loading the library.
In Emacs 31, doing the latter will no longer work.  (Bug#73291)

(cherry picked from commit 76c6b4d2799ab1396ba003d33e4a177519d7e53d)

diff --git a/lisp/midnight.el b/lisp/midnight.el
index 6e1e7b5ccb7c69c9537d37b895808b2cbddd153e..ea30f5462f224c9b2220c6dac1eb171a9dbad8ad 100644 (file)
--- a/lisp/midnight.el
+++ b/lisp/midnight.el
@@ -1,6 +1,6 @@
 ;;; midnight.el --- run something every midnight, e.g., kill old buffers  -*- lexical-binding:t -*-
 
-;; Copyright (C) 1998, 2001-2024 Free Software Foundation, Inc.
+;; Copyright (C) 1998-2024 Free Software Foundation, Inc.
 
 ;; Author: Sam Steingold <sds@gnu.org>
 ;; Created: 1998-05-18
@@ -23,7 +23,7 @@
 
 ;;; Commentary:
 
-;; To use the file, put (require 'midnight) into your .emacs.  Then, at
+;; To use the file, put (midnight-mode) into your .emacs.  Then, at
 ;; midnight, Emacs will run the normal hook `midnight-hook'.  You can
 ;; put whatever you like there, say, `calendar'; by default there is
 ;; only one function there - `clean-buffer-list'.  It will kill the