fix clippy

Author: Mason Liang

src/gadgets/mpt_update/assign.rs

@@ -254,7 +254,7 @@ impl MptUpdateConfig {
             }
         };
         self.assign_storage(region, next_offset, &proof.storage, randomness);
-        return proof.n_rows();
+        proof.n_rows()
     }
 
     // Valid assignment proving that the address 0 doesn't exist in an empty MPT.

src/mpt.rs

@@ -122,10 +122,10 @@ impl MptCircuitConfig {
     ) -> Result<(), Error> {
         let randomness = self.rlc_randomness.value(layouter);
 
-        let proofs_vec: Vec<_> = proofs.iter().cloned().collect();
         layouter.assign_regions(
             || "mpt circuit parallel assignment 1",
-            self.mpt_update.assignments(proofs_vec, n_rows, randomness),
+            self.mpt_update
+                .assignments(proofs.to_vec(), n_rows, randomness),
         )?;
 
         let (u32s, u64s, u128s, frs) = byte_representations(proofs);