crypto: trait tweaks for HpkeSuite, HpkePublicKey

The `HpkeSuite` type is small enough to be a candidate for `Copy`. The
`HpkePublicKey` type should be `Debug` and `Clone` so we can easily use
it for GREASE ECH configurations.

rustls/src/crypto/hpke.rs

@@ -26,7 +26,7 @@ pub trait HpkeProvider: Debug + Send + Sync + 'static {
 }
 
 /// An HPKE suite, specifying a key encapsulation mechanism and a symmetric cipher suite.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Copy)]
 pub struct HpkeSuite {
     /// The choice of HPKE key encapsulation mechanism.
     pub kem: HpkeKem,
@@ -110,6 +110,7 @@ pub trait HpkeOpener: Debug + Send + Sync + 'static {
 }
 
 /// An HPKE public key.
+#[derive(Debug, Clone)]
 pub struct HpkePublicKey(pub Vec<u8>);
 
 /// An HPKE private key.