RSA: Stop deriving Clone and Copy for P, Q, and N.

This was an artifact of some old logic that's no longer needed.

src/rsa.rs

@@ -55,7 +55,6 @@ fn parse_public_key(
 
 // Type-level representation of an RSA public modulus *n*. See
 // `super::bigint`'s modulue-level documentation.
-#[derive(Copy, Clone)]
 enum N {}
 
 impl bigint::PublicModulus for N {}

src/rsa/keypair.rs

@@ -492,10 +492,8 @@ fn elem_exp_consttime<M>(
 // Type-level representations of the different moduli used in RSA signing, in
 // addition to `super::N`. See `super::bigint`'s modulue-level documentation.
 
-#[derive(Copy, Clone)]
 enum P {}
 
-#[derive(Copy, Clone)]
 enum Q {}
 
 enum D {}