Added remaining stats to the garbage command.

[data-pup]

Adding stats calculation to the garbage sub-command's "... and X more" row. Also add's the remaining/total rows to the JSON output to match the behavior of other sub-commands.

Note: This doesn't clean things up to remove duplicated logic from the Emit trait the same way some of the other PR's have, but that can be done soon 😄

[fitzgen]

Note: This doesn't clean things up to remove duplicated logic from the Emit trait the same way some of the other PR's have, but that can be done soon smile

👍 💖

[fitzgen]

Thanks as always @data-pup :)

r=me with nitpick below addressed!

[fitzgen]

Nitpick: I think this would be a bit more readable as

let (size, cnt) = self
    .items
    .iter()
    .skip(self.limit)
    .map(|id| &items[*id])
    .fold((0, 0), |(size, cnt), item| (size + item.size(), cnt + 1));
if cnt > 0 {
    ...
}