cli in cargo run -- mode --help and cargo run -- --help is misleading

[jamesray1]

We will need to update to be able to use cli as a command, or update these help instructions. But this isn't a high priority as we are not production ready.

cargo run -- mode --help
// Snipped DEBUG outputs
cli-mode
Choose mode(s) to run the sharding node

USAGE:
    cli mode [FLAGS]

FLAGS:
    -b, --both        both proposer and notary modes
    -h, --help        Prints help information
    -n, --notary      notary mode
    -p, --proposer    proposer mode
    -V, --version     Prints version information

$ cargo run -- --help
    Finished dev [unoptimized + debuginfo] target(s) in 0.09 secs
     Running `target/debug/cli --help`
Processing arguments: ["--help"]
// Snipped DEBUG lines
diamond-drops-cli 0.1.0-a
James Ray (@jamesray1), Josiah (@ChosunOne), Luke Schoen (@ltfschoen)
Implementation of Ethereum Sharding in Rust

USAGE:
    cli [OPTIONS] [SUBCOMMAND]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
    -l, --log <LOG>    Set logging verbosity to error 0, warn 1, debug 2, info 3, or trace 4

SUBCOMMANDS:
    help    Prints this message or the help of the given subcommand(s)
    mode    Choose mode(s) to run the sharding node
$ cli mode -b
bash: cli: command not found