`aio runtime:list` should be documented

[MichaelGoberling]

Describe the bug The aio runtime:list command is not present when running aio runtime --help. It is also not documented as part of the README.md of this repo.

To Reproduce Steps to reproduce the behavior:

1. Run aio runtime --help
2. Notice that aio runtime:list is not listed under topics or commands.

Expected behavior aio runtime:list should show up under topics or commands, it should also be documented as part of the README.md of this repo.

Screenshots

Desktop (please complete the following information):

• OS: macOS 12.1 (21C52)

[shazron]

aio runtime list is actually an alias for aio runtime:namespace:get.

See aio runtime list --help:

❯ aio runtime list --help
Get triggers, actions, and rules in the registry for namespace

USAGE
  $ aio runtime:namespace:get

OPTIONS
  -i, --insecure           bypass certificate check
  -n, --name               sort results by name
  -u, --auth=auth          whisk auth
  -v, --verbose            Verbose output
  --apihost=apihost        whisk API host
  --apiversion=apiversion  whisk API version
  --cert=cert              client cert
  --debug=debug            Debug level output
  --help                   Show help
  --json                   output raw json
  --key=key                client key
  --name-sort              sort results by name
  --version                Show version

ALIASES
  $ aio rt:get
  $ aio runtime:list
  $ aio rt:list
  $ aio runtime:ls
  $ aio rt:ls

Only actual commands (and not aliases) are listed in aio runtime --help