It's Clippy time (#3806)

Fix some Clippy issues

substrate/core/primitives/src/ed25519.rs

@@ -41,6 +41,7 @@ use crate::{crypto::{Public as TraitPublic, UncheckedFrom, CryptoType, Derive}};
 type Seed = [u8; 32];
 
 /// A public key.
+#[cfg_attr(feature = "std", derive(Hash))]
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Encode, Decode, Default)]
 pub struct Public(pub [u8; 32]);
 
@@ -152,13 +153,6 @@ impl<'de> Deserialize<'de> for Public {
 	}
 }
 
-#[cfg(feature = "std")]
-impl std::hash::Hash for Public {
-	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-		self.0.hash(state);
-	}
-}
-
 /// A signature (a 512-bit value).
 #[derive(Encode, Decode)]
 pub struct Signature(pub [u8; 64]);