clippy: Remove unneeded ?Sized bound and replace never type with () (#1758)

* storage: Remove ?Sized bound

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* backend: Use () instead of !

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* backend: Return directly

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

---------

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

core/src/storage/storage_key.rs

@@ -182,7 +182,7 @@ impl<K: codec::Encode + ?Sized> StaticStorageKey<K> {
     }
 }
 
-impl<K: codec::Decode + ?Sized> StaticStorageKey<K> {
+impl<K: codec::Decode> StaticStorageKey<K> {
     /// Decodes the encoded inner bytes into the type `K`.
     pub fn decoded(&self) -> Result<K, Error> {
         let decoded = K::decode(&mut self.bytes())?;

subxt/src/backend/legacy/rpc_methods.rs

@@ -332,8 +332,7 @@ impl<T: Config> LegacyRpcMethods<T> {
         public: Vec<u8>,
     ) -> Result<(), Error> {
         let params = rpc_params![key_type, suri, Bytes(public)];
-        self.client.request("author_insertKey", params).await?;
-        Ok(())
+        self.client.request("author_insertKey", params).await
     }
 
     /// Generate new session keys and returns the corresponding public keys.

subxt/src/backend/unstable/rpc_methods.rs

@@ -77,9 +77,7 @@ impl<T: Config> UnstableRpcMethods<T> {
                 "chainHead_v1_continue",
                 rpc_params![follow_subscription, operation_id],
             )
-            .await?;
-
-        Ok(())
+            .await
     }
 
     /// Stops an operation started with `chainHead_v1_body`, `chainHead_v1_call`, or
@@ -97,9 +95,7 @@ impl<T: Config> UnstableRpcMethods<T> {
                 "chainHead_v1_stopOperation",
                 rpc_params![follow_subscription, operation_id],
             )
-            .await?;
-
-        Ok(())
+            .await
     }
 
     /// Call the `chainHead_v1_body` method and return an operation ID to obtain the block's body.
@@ -222,9 +218,7 @@ impl<T: Config> UnstableRpcMethods<T> {
     ) -> Result<(), Error> {
         self.client
             .request("chainHead_v1_unpin", rpc_params![subscription_id, hash])
-            .await?;
-
-        Ok(())
+            .await
     }
 
     /// Return the genesis hash.