Fix display of R2L buffer names in Buffer-menu.

Fix display of R2L buffer names in Buffer-menu.

 lisp/buff-menu.el (Buffer-menu-buffer+size): Accept an additional
 argument LRM; if non-nil, append an invisible LRM character to the
 buffer name.
 (list-buffers-noselect): Call Buffer-menu-buffer+size with the
 last argument non-nil, when formatting buffer names.