Fix clippy warnings (#1385)

## Issue Addressed

NA

## Proposed Changes

Fixes most clippy warnings and ignores the rest of them, see issue #1388.

beacon_node/store/src/chunked_vector.rs

@@ -381,6 +381,7 @@ pub fn store_updated_vector<F: Field<E>, E: EthSpec, S: KeyValueStore<E>>(
     Ok(())
 }
 
+#[allow(clippy::too_many_arguments)]
 fn store_range<F, E, S, I>(
     _: F,
     range: I,

beacon_node/store/src/forwards_iter.rs

@@ -78,7 +78,7 @@ impl SimpleForwardsBlockRootsIterator {
                     .collect::<Vec<_>>()
             },
         )?;
-        Ok(Self { values: values })
+        Ok(Self { values })
     }
 }
 

beacon_node/store/src/leveldb_store.rs

@@ -77,7 +77,7 @@ impl<E: EthSpec> KeyValueStore<E> for LevelDB<E> {
     }
 
     fn sync(&self) -> Result<(), Error> {
-        self.put_bytes_sync("sync", "sync".as_bytes(), "sync".as_bytes())
+        self.put_bytes_sync("sync", b"sync", b"sync")
     }
 
     /// Retrieve some bytes in `column` with `key`.
@@ -108,7 +108,7 @@ impl<E: EthSpec> KeyValueStore<E> for LevelDB<E> {
         self.db
             .get(self.read_options(), BytesKey::from_vec(column_key))
             .map_err(Into::into)
-            .and_then(|val| Ok(val.is_some()))
+            .map(|val| val.is_some())
     }
 
     /// Removes `key` from `column`.

beacon_node/store/src/partial_beacon_state.rs

@@ -75,7 +75,7 @@ impl<T: EthSpec> PartialBeaconState<T> {
             genesis_time: s.genesis_time,
             genesis_validators_root: s.genesis_validators_root,
             slot: s.slot,
-            fork: s.fork.clone(),
+            fork: s.fork,
 
             // History
             latest_block_header: s.latest_block_header.clone(),
@@ -107,9 +107,9 @@ impl<T: EthSpec> PartialBeaconState<T> {
 
             // Finality
             justification_bits: s.justification_bits.clone(),
-            previous_justified_checkpoint: s.previous_justified_checkpoint.clone(),
-            current_justified_checkpoint: s.current_justified_checkpoint.clone(),
-            finalized_checkpoint: s.finalized_checkpoint.clone(),
+            previous_justified_checkpoint: s.previous_justified_checkpoint,
+            current_justified_checkpoint: s.current_justified_checkpoint,
+            finalized_checkpoint: s.finalized_checkpoint,
         }
     }