kcms/notifications: explain extra duration time for certain popups
Notifications with URLs (e.g. for images, files, or locations on disk) get an extra 5 seconds of visibility before disappearing, so you have extra time to interact with them.
But this isn't explained in the UI anywhere despite the fact that we allow the user to customize notifications' duration, so as a result, when some notifications don't respect this setting, it seems like a random bug to the user.
Let's add an explanation right next to the place where people customize the time, so it's clear what will happen and won't seem so random.
BUG: 464515 FIXED-IN: 6.0
Edited by Nate Graham