[rustup] subcommands are missing required arguments and autocompletion suggestions

[neoncitylights]

Sanity checks

• [X] My issue relates to a specific CLI completion spec (e.g. git checkout is missing options in git completion spec). If your issue is more general, please create your issue here: withfig/fig
• [X] I have searched github.com/withfig/autocomplete/issues and there are no duplicates of my issue
• [X] I would like to work on this.

What CLI tool does this relate to?

rustup

Which statement makes the most sense?

There are errors with this completion spec

Issue Details

I found some issues with the rustup CLI spec, after initially trying to run rustup component add:

• --version: this option is not available in every subcommand context, only at the root (via rustup --version)
• rustup help + rustup <subcommand> help: does not suggest subcommands
• rustup check: does not accept any arguments, but is listed as so in the spec
• rustup component list: accepts an optional --installed option, but isn't listed
• rustup component <add|remove>: both subcommands require a <component> argument, but isn't listed
• rustup default: requires a <toolchain> argument, but isn't listed
• rustup man: requires a <subcommand> argument, but isn't listed
• rustup override <set|unset>: both subcommands require a <toolchain> argument, but it isn't listed
• rustup self uninstall: accepts a -y option, but isn't listed
• rustup set: accepts a profile subcommand, but profile isn't listed
• rustup target <add|remove>:
  • Minor typo in the toolchain argument name: <toolchain instead of <toolchain>
  • Does not provide suggestions for common targets like stable and nightly
• rustup toolchain link <toolchain> <path>: path accepts a directory, but doesn't suggest any
• rustup toolchain list: missing optional --verbose option which lists extra information about toolchains

[mschrage]

Hey @neoncitylights! Thanks for taking the initiative on this. Let me know if you get stuck on anything :)