Prefer :risky defcustom keyword

Prefer :risky defcustom keyword

* lisp/align.el (align-region-separate, align-rules-list)
(align-exclude-rules-list, align-vhdl-rules-list):
* lisp/bindings.el (mode-line-percent-position):
* lisp/filesets.el (filesets-menu-cache-file, filesets-commands)
(filesets-external-viewers, filesets-ingroup-patterns)
(filesets-data):
* lisp/hi-lock.el (hi-lock-file-patterns-policy):
* lisp/mail/mailalias.el (mail-complete-alist)
(mail-directory-process, mail-directory-stream)
(mail-directory-parser):
* lisp/mail/rmail.el (rmail-confirm-expunge):
* lisp/mail/sendmail.el (mail-signature):
* lisp/mail/supercite.el (sc-cite-frame-alist)
(sc-uncite-frame-alist, sc-recite-frame-alist)
(sc-default-cite-frame, sc-default-uncite-frame)
(sc-default-recite-frame, sc-attrib-selection-list)
(sc-rewrite-header-list):
* lisp/progmodes/make-mode.el (makefile-special-targets-list):
* lisp/so-long.el (so-long-action-alist):
* lisp/textmodes/sgml-mode.el (sgml-tag-alist): Prefer defcustom
:risky keyword argument to directly setting the 'risky-local-variable'
symbol property.