Verb subcommands should show help text in absence of argument

[sampeinado]

Problem

Today when you type a noun subcommand (ex. kp image), the help text for that command prints by default, but when you add a verb onto that noun subcommand (ex. kp image status), an error prints.

Example:

Instead of printing an error when an argument is missing, we should print the help text associated with that verb subcommand, as if the user had typed the -h flag.

We can still print an error (ex. Error: accepts 1 arg(s), received 0), but we should also print the help text and state WHICH arg is missing.

Example:

Mockup of potential solution:

When a verb subcommand does not have the necessary args, help text and an error message are printed together.

$kp image status
Error: accepts 1 arg(s) - <name>, received 0

`kp image status` prints detailed information about the status of a specific image in the provided namespace.

namespace defaults to the kubernetes current-context namespace.

Usage:
  kp image status <name> [flags]

Examples:
kp image status my-image
kp image status my-other-image -n my-namespace

Flags:
  -h, --help               help for status
  -n, --namespace string   kubernetes namespace

Alternative solution:

Provide a human readable error message that explains why the error happened and what you can do about it. For example:

$ kubectl describe
error: You must specify the type of resource to describe. Use "kubectl api-resources" for a complete list of supported resources.