docs(cli): update --as expectations

[grypez]

          I see, although in this case it's the README that's wrong; `--as` was omitted from `list` in a deliberate design decision. I noticed the discrepancy myself a while back and even put up a PR for it (#2228), but we decided against making the change at the time. I don't think the situation is likely to change unless we complete a more thorough audit of each command for `--as` support, and until then I think it makes the most sense to update the readme and these tests.

Originally posted by @rekmarks in #2384 (comment)