Adds ugly/annoying desktop notifications to Messenger.
Before Facebook Messenger was reskinned in 2020(?), it supported desktop notifications. After the reskin, it lost search and notification functionality. They readded search functionality (sometime before 2021-09-17), but still haven’t reimplemented desktop notifications. They only have sounds (which I like to keep disabled).
This script is annoying and will renotify you about 2/3 times per notification and will lag behind. But it is better than going for hours without noticing that you received messages!