fix: append notification instead of prepend in notifications popup example

[datsfilipe]

I believe the notification should be added at the end of the notifications list, this way the oldest notifications are destroyed first, instead of the newest ones.

I was using this example in my dotfiles when I noticed this and this change made it work for me. If you feel this change is not necessary or not a suitable solution, simply close this.

[Aylur]

its just a preference really, I prepend it so that it appears at the top of the list like they do usually on other platforms it shouldn't affect which item is destroyed dismiss since its picked by id and not position in the array