* etc/NEWS: Document new Prettify Symbols mode.
* lisp/progmodes/prog-mode.el (prettify-symbols-alist): Rename from
`prog-prettify-symbols', and make a local defvar instead of defcustom.
(prettify-symbols--keywords): Rename from `prog-prettify-symbols-alist'
and make a local defvar.
(prettify-symbols--compose-symbol): Rename from
`prog--prettify-font-lock-compose-symbol'.
(prettify-symbols--make-keywords): Rename from
`prog-prettify-font-lock-symbols-keywords' and simplify.
(prog-prettify-install): Remove.
(prettify-symbols-mode): New minor mode, based on `prog-prettify-install'.
(turn-on-prettify-symbols-mode): New function.
(global-prettify-symbols-mode): New globalized minor mode.
* lisp/emacs-lisp/lisp-mode.el (lisp-mode-variables):
* lisp/progmodes/cfengine.el (cfengine3-mode):
* lisp/progmodes/perl-mode.el (perl-mode): Don't call `prog-prettify-install';
set `prettify-symbols-alist' instead.
(prog-prettify-install): Add `composition' to `font-lock-extra-managed-props'
if any prettifying keyword is added.
(prog--prettify-font-lock-compose-symbol): Use ?\s instead of ?\ .
(prog-mode): Use `setq-local'.