Fix doc for CryptoStore::ecdsa_sign_prehashed() (#8876)

* fix ecdsa_sign_prehashed() doc

* document both instances

substrate/primitives/core/src/lib.rs

@@ -336,7 +336,7 @@ impl From<LogLevel> for log::Level {
 
 /// Log level filter that expresses which log levels should be filtered.
 ///
-/// This enum matches the [`log::LogLevelFilter`] enum.
+/// This enum matches the [`log::LevelFilter`] enum.
 #[derive(Encode, Decode, PassByEnum, Copy, Clone)]
 pub enum LogLevelFilter {
 	/// `Off` log level filter.

substrate/primitives/keystore/src/lib.rs

@@ -195,13 +195,18 @@ pub trait CryptoStore: Send + Sync {
 		transcript_data: VRFTranscriptData,
 	) -> Result<Option<VRFSignature>, Error>;
 
-	/// Sign pre-hashed
+	/// Generate an ECDSA signature for a given pre-hashed message.
 	///
-	/// Signs a pre-hashed message with the private key that matches
+	/// Receives [`KeyTypeId`] and an [`ecdsa::Public`] key to be able to map
-	/// the ECDSA public key passed.
+	/// them to a private key that exists in the keystore. This private key is,
+	/// in turn, used for signing the provided pre-hashed message.
 	///
-	/// Returns the SCALE encoded signature if key is found and supported,
+	/// The `msg` argument provided should be a hashed message for which an
-	/// `None` if the key doesn't exist or an error when something failed.
+	/// ECDSA signature should be generated. 
+	/// 
+	/// Returns an [`ecdsa::Signature`] or `None` in case the given `id` and
+	/// `public` combination doesn't exist in the keystore. An `Err` will be
+	/// returned if generating the signature itself failed.
 	async fn ecdsa_sign_prehashed(
 		&self,
 		id: KeyTypeId,
@@ -368,13 +373,18 @@ pub trait SyncCryptoStore: CryptoStore + Send + Sync {
 		transcript_data: VRFTranscriptData,
 	) -> Result<Option<VRFSignature>, Error>;
 
-	/// Sign pre-hashed
+	/// Generate an ECDSA signature for a given pre-hashed message.
 	///
-	/// Signs a pre-hashed message with the private key that matches
+	/// Receives [`KeyTypeId`] and an [`ecdsa::Public`] key to be able to map
-	/// the ECDSA public key passed.
+	/// them to a private key that exists in the keystore. This private key is,
+	/// in turn, used for signing the provided pre-hashed message.
 	///
-	/// Returns the SCALE encoded signature if key is found and supported,
+	/// The `msg` argument provided should be a hashed message for which an
-	/// `None` if the key doesn't exist or an error when something failed.
+	/// ECDSA signature should be generated. 
+	/// 
+	/// Returns an [`ecdsa::Signature`] or `None` in case the given `id` and
+	/// `public` combination doesn't exist in the keystore. An `Err` will be
+	/// returned if generating the signature itself failed.
 	fn ecdsa_sign_prehashed(
 		&self,
 		id: KeyTypeId,