New command 'crm-complete-and-insert-separator'

New command 'crm-complete-and-insert-separator'

* lisp/emacs-lisp/crm.el (crm-complete-and-insert-separator): New
command.
(completing-read-multiple-mode-map): Bind it to 'C-,'.
(crm-canonical-separator, crm-common-separators): New variables.
(completions-multi-mode): Adapt mode line lighter.
(crm-complete-and-exit): Only suggest in 'M-x' in 'minibuffer-mode'.
(crm-change-separator): (Re)set canonical separator.

* doc/lispref/minibuf.texi (Minibuffer Completion): Update.
* doc/emacs/mini.texi (Completion Multi): New subsection.
(Completion Commands): Fix markup.
(Completion)
* doc/emacs/emacs.texi (Top): Add menu entry.

* etc/NEWS: Announce 'crm-complete-and-insert-separator'.