Describe the feature or problem you’d like to solve

When using the terminal view for gh issue view and gh pr view (currently requiring the --preview flag but soon to be the default), there's a lot of metadata that does not show up in the output that would be helpful to people.

Proposed solution

Mirroring most of the information in the issue/PR sidebar seems sensible as a starting point, but I have no opinion about how it should be presented.

cc: @ampinsk

Additional context

We're removing the labels from immediately below the header in #652, so this will be more useful when that ships.