Prefer Emacs mouse button event names to XEmacs names

* lisp/mwheel.el:
* lisp/vc/ediff-mult.el (ediff-meta-buffer-verbose-message)
(ediff-draw-dir-diffs, ediff-redraw-registry-buffer): Prefer Emacs
mouse button event names to XEmacs names.

lisp/bs.el

 ;;; bs.el --- menu for selecting and displaying buffers -*- lexical-binding: t -*-
 
 ;; Copyright (C) 1998-2022 Free Software Foundation, Inc.
+
 ;; Author: Olaf Sylvester <Olaf.Sylvester@netsurf.de>
 ;; Maintainer: emacs-devel@gnu.org
 ;; Keywords: convenience

lisp/mwheel.el

 ;;; mwheel.el --- Mouse wheel support  -*- lexical-binding:t -*-
 
-;; Copyright (C) 1998, 2000-2022 Free Software Foundation, Inc.
+;; Copyright (C) 1998-2022 Free Software Foundation, Inc.
+
 ;; Keywords: mouse
 ;; Package: emacs
 
@@ -22,7 +23,7 @@
 ;;; Commentary:
 
 ;; This enables the use of the mouse wheel (or scroll wheel) in Emacs.
-;; Under X11/X.Org, the wheel events are sent as button4/button5
+;; Under X11/X.Org, the wheel events are sent as mouse-4/mouse-5
 ;; events.
 
 ;; Mouse wheel support is already enabled by default on most graphical
@@ -32,7 +33,7 @@
 
 ;; Implementation note:
 ;;
-;; I for one would prefer some way of converting the button4/button5
+;; I for one would prefer some way of converting the mouse-4/mouse-5
 ;; events into different event types, like 'mwheel-up' or
 ;; 'mwheel-down', but I cannot find a way to do this very easily (or
 ;; portably), so for now I just live with it.

lisp/vc/ediff-mult.el

@@ -128,7 +128,7 @@
 (defconst ediff-meta-buffer-verbose-message "Ediff Session Group Panel: %s
 
 Useful commands (type ? to hide them and free up screen):
-     button2, v, or RET over session record:   start that Ediff session
+     mouse-2, v, or RET over session record:   start that Ediff session
      M:\tin sessions invoked from here, brings back this group panel
      R:\tdisplay the registry of active Ediff sessions
      h:\tmark session for hiding (toggle)
@@ -1236,7 +1236,7 @@ behavior."
       (insert "\t\t*** Directory Differences ***\n")
       (insert "
 Useful commands:
-  C,button2: over file name -- copy this file to directory that doesn't have it
+  C,mouse-2: over file name -- copy this file to directory that doesn't have it
           q: hide this buffer
       n,SPC: next line
       p,DEL: previous line\n\n")
@@ -1429,7 +1429,7 @@ Useful commands:
 This is a registry of all active Ediff sessions.
 
 Useful commands:
-     button2, `v', RET over a session record:  switch to that session
+     mouse-2, `v', RET over a session record:  switch to that session
      M over a session record:  display the associated session group
      R in any Ediff session:   display session registry
      n,SPC: next session