* lisp/progmodes/perl-mode.el (perl-prettify-symbols): New defcustom.

* lisp/progmodes/perl-mode.el (perl-prettify-symbols): New defcustom.
(perl--prettify-symbols-alist): New const.
(perl--font-lock-compose-symbol, perl--font-lock-symbols-keywords): New funs.
(perl-font-lock-keywords-2): Use them.
(perl-electric-noindent-p): New function.
(perl-mode): Use it to set up electric-indent-mode.
(perl-electric-terminator, perl-indent-command): Mark obsolete.
(perl-mode-map): Remove bindings for them.
(perl-imenu-generic-expression, perl-outline-level):
Match functions&packages in column>0.