Option to clear notification after a certain time interval #118

Checking the API shows there's no option to clear popups after a certain period of time's elapsed.

Basically, I was hoping to override the "Scopes at Cursor" command with something similar that would disappear after a few brief seconds (I'm neck-deep in developing a full-on language grammar... not having to kick the dev tools open to inspect where tokens end and begin is really helpful).

I noticed in #73 there's a method for clearing notifications, but as it's not documented, I'm not sure how much I can depend on it always being there...

Anyway, I realised it'd be helpful to have a user setting to hide all notifications after a certain time-frame (perhaps type-sensitive: shorter periods of time could be set for notices, with errors receiving longer/unlimited durations, etc).