Update quickurl.el

Update quickurl.el

* lisp/net/quickurl.el (quickurl-format-function):
(quickurl-sort-function): Use named function.
(quickurl-list-mode-map): Remove lines that are extraneous now that the
parent mode is special-mode.
(quickurl-format-url, quickurl-sort-urls): New functions.
(quickurl-read, quickurl): Use defun, as no cl-defun feature appears to
be used.
(quickurl-list-mode): Derive from special-mode.  Nix setting
buffer-read-only: special-mode does that.
(quickurl-list-populate-buffer): Use dolist instead.
(quickurl-list-quit): Use quit-window.  It looks like this was written
before the quit-window rewrite.  quit-window is very useful now.