Implement new notifications UX

[bpasero]

[lukewis]

@bpasero , are there any docs on the keyboard accessibility? I've been trying to figure out how to get the keyboard to dismiss a notification, but I'm coming up empty.

[bpasero]

@lukewis here are the keybindings:

[lukewis]

@bpasero Wow. Never knew that existed. Opened up a whole new world for me! Thanks for helping out a newbie!

[ndarilek]

VSCode newbie here. I'm a screen reader user and am struggling with this issue. After chasing it through several closed/locked issues, I've found this PR, which includes an image I can't read of the relevant keybindings. :)

First, is this fix available in whatever version I'd get if I go to the download page and perform a fresh install? I don't have the relevant VM booted so I'm not sure what version I have, or if I still need to be on the insider build. This installation is new as of yesterday, so is fairly representative of what a new user would get.

Then, how do I go about interacting with notifications via the keyboard? I can tab to them, but any yes/no notifications are unusable to me. Ironically I hit this with the initial "Are you using a screen reader?" notification, which I couldn't click Yes on. :) I've looked through accessibility documentation, but haven't found anything about interacting with notifications.

Thanks.