* lisp/desktop.el: Make use some "new" functionality
(desktop-files-not-to-save, desktop-clear):
Use \` and \' when we don't intend to match newlines.
(desktop-minor-mode-table): Remove auto-fill-function entry.
(desktop-buffer-info): Use :minor-mode-function instead.
(desktop--v2s): Use a closure rather than a backquoted lambda.
(desktop-save): Set 'lexical-binding' in the saved file.
Use 'utf-8-emacs' encoding rather than the old 'emacs-mule'.
(desktop-read): Use 'default-value' to get the global part of a hook.