For our docs we want to produce nice screenshots like these:

This was made using cmd-shift-4 on a Mac. Note the transparent background with the shadow.

It would be great to have a simple, unified method to produce these screenshots across different OS:es, available via a the command palette and a keyboard shortcut.

We could, for instance, just read back the framebuffer, round the edges, add some spacing and shadow, and then save that as a png. We wouldn't get the mac-style close buttons though (the red,yellow,green in the top left), so we would need something like #1063 for that, or just fake it