lisp/(cus-edit,custom).el: Fix typos; use setq-local, string-match-p, looking-at-p.

lisp/(cus-edit,custom).el: Fix typos; use setq-local, string-match-p, looking-at-p.

* lisp/cus-edit.el:
  (custom-commands): Fix typos.
  (custom-display): Fix tooltip text.
  (custom-magic-alist, custom-filter-face-spec, custom-group-members):
  Fix typos in docstrings.
  (custom--initialize-widget-variables, Custom-mode): Use `setq-local'.
  (custom-unlispify-menu-entry, custom-magic-value-create)
  (custom-add-see-also, custom-group-value-create): Use ?\s.
  (custom-guess-type, customize-apropos, editable-field)
  (custom-face-value-create): Use `string-match-p'.
  (custom-save-variables, custom-save-faces): Use `looking-at-p'.

* lisp/custom.el (custom-load-symbol): Use `string-match-p'.