Add command description to cargo --list

When running `cargo --list` the `cargo upgrade` and `cargo set-version` commands do not have any description.

See screenshot:

I suggest adding a description.

Thanks for making this program it's cool :)

Start by locating where the `cargo upgrade` and `cargo set-version` subcommands register their CLI metadata, then inspect the generated output for `cargo --list`. Add descriptions for both commands and verify that they appear correctly when running `cargo --list`.

Written by the indexing model from the issue text.