Match nightly cargo's help output for `cargo-clippy`

[epage]

Summary

rust-lang/cargo#12578 updated --help to match other styling of cargo. rust-lang/rustfmt#5908 updates rustfmt to match. Since clippy doesn't use clap, I wasn't sure what the right approach clippy would prefer so instead creating this here.

Reproducer

Once its in a nightly, compare

$ cargo +nightly check -h
$ cargo +nightly clippy -h

Until then:

$ cargo run --manifest-path cargo/Cargo.toml -- check -h
$ cargo +nightly clippy -h

Version

Help styling was merged into cargo as of c2d26f32d

Additional Labels

No response

[blyxyas]

@rustbot claim