Dunst: Allow stacking with -a or -c using notify-send

[Anachron]

It would be awesome to allow stacking of notifications using a custom ID.

There is already -a for app and -c for category in notify-send, which could be used for this.

[WhyNotHugo]

Doesn't dunstify work for your scenario?

[Anachron]

Based on @tsipinakis dunstify can break my stuff any release and is only meant for debugging.
Plus on the distro I'm on (Void Linux) dunstify isn't compiled.

[bebehei]

Stacking is now possible with the stack_tag feature implemented in #552.

Send a hint with notify-send --hint=string:x-dunst-stack-tag:test SUMMARY BODY. And all notifications with the stack tag test get stacked on top of each other.

You can have whatever stack tags you want. Common stack tags are volume and many more.

[Anachron]

Thank you so much!