Return -s (mod L)
pub fn neg(s: CompressedScalar, endian: std.builtin.Endian) NonCanonicalError!CompressedScalar
pub fn neg(s: CompressedScalar, endian: std.builtin.Endian) NonCanonicalError!CompressedScalar { return (try Scalar.fromBytes(s, endian)).neg().toBytes(endian); }