Specify undo toast behavior
At some point, though I don't remember where, there was a mockup that did undo as follows:
I.e. quickly deleting multiple items results in a single toast with a single undo button. That's what libadwaita docs and demo showcase, but it looks like it never made it to the hig, and apps all do different things:
- Nautilus just dismisses the previous toast, so the first item is lost completely when you delete the second one
- Loupe queues them, so if you delete 5 items, you get 5 toasts
- Contacts seems to just be broken:
and so on.
So, either it needs to be documented, or if we want sth different, then that needs to be documented instead.