Revert to use the notifications library by default.
The alert library project itself mentions that:
For desktop notifications, the notifications package that is installed with emacs, provides a probably better alternative for most users.
and it appears true, as by default alert' simply print notification messages to the
Messages' buffer, which is not exactly a desktop
notification.
- gnus-desktop-notify.el (require): Require notifications first, falling back to alert. (gnus-desktop-notify-function): Test for the notifications feature first. Mention `notifications' is the default in its doc.