squashed commit

- fix compiler warnings about unused #[inline]
- spelling fix
- rustfmt change
- remove trait bounds on the ConstantTimeLess trait declaration itself
- implement ConstantTime{Less,Greater} with shortlex too
- improve comments on ct_gt impl
- remove extraneous mentions of shortlex
- iterated operations
- revert ConstantTimeLess back to using the default trait method
- remove `.unwrap_u8()`: does this break `ConstantTimeEq` slice impl?