perf(help): Reduce colorless code size
perf(help): Reduce colorless code size

This takes off another 14 KiB when color us not used.  My hope is that
we'll be able to switch away from `termcolor` to a term styling crate
that will make this work in the color case as well.

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