test(derive): No longer supporting some wrapped types
test(derive): No longer supporting some wrapped types

With the new `ArgMatches`, we need to know what the inner type is.

Unfortunately, #3142 didn't list use cases for this.  We dropped the
`Option` alias changing `T` but we still have a `Result` in there that
is aliased.

One potential workaround if people need it is if we add an attribute to
specify the `get_many::<T>` type.  This would also help with
`ArgAction::Count` to support more data types.

clap-rs/clap,clap-rs/clap,clap-rs/clap