Add the ability to add alternative names for subcommand variants with #[clap] attribute

[mitchmindtree]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Clap Version

3.1.9

Describe your use case

It would be nice if we could add alternative names for subcommands.

E.g. a Build(BuildCmd) command for cargo might offer:

cargo build

It would be nice if we could easily add shorthand aliases for this command. E.g.

cargo b

I believe this is currently possible for options, but I didn't come across a solution for subcommands.

Currently, the only solution I'm aware of for aliasing subcommands is to add further variants, e.g.

    Build(BuildCmd),
    B(BuildCmd),

however I think we run into duplicated help docs here.

Describe the solution you'd like

Perhaps something along the lines of

    #[clap(alias = "b")]
    Build

Or something like:

    #[clap(short)]
    Build

or

    #[clap(short = "b")]

By having a dedicated macro, we could generate dedicated documentation that describes the command is an alias or shorthand for the longer form.

Alternatives, if applicable

No response

Additional Context

No response

[epage]

On the derive-reference, we explain under "Raw attributes" that any Command builder method can be used as an attribute.

If you then go over to Command, you'll see a link for subcommand settings, scroll down, and you'll see we have an alias method.

Both of these combined mean you can do

    #[clap(alias = "b")]
    Build

though that doesn't show up in the help by default. For that, you are looking for

    #[clap(visible_alias = "b")]
    Build

[mitchmindtree]

Ahh thanks for the quick response, and apologies for the oversight! Hopefully this issue at leasts helps another clap wanderer in the future.