clippy: fix redundant_closure_for_method_calls lint

Essentially just a style thing; I think it's nicer to be explicit about
what type we're calling methods on, and I think it's nicer to avoid the
closure syntax when we can.

Author: apoelstra

src/blind.rs

@@ -715,12 +715,13 @@ impl TxOut {
     {
         let value_blind_inputs = spent_utxo_secrets
             .iter()
-            .map(|utxo_sec| utxo_sec.value_blind_inputs())
+            .map(TxOutSecrets::value_blind_inputs)
             .collect::<Vec<_>>();
 
         let value_blind_outputs = output_secrets
             .iter()
-            .map(|e| e.value_blind_inputs())
+            .copied()
+            .map(TxOutSecrets::value_blind_inputs)
             .collect::<Vec<_>>();
 
         let out_vbf = ValueBlindingFactor::last(

src/pset/map/input.rs

@@ -481,7 +481,7 @@ impl Input {
         self.sighash_type
             .map_or(
                 Some(EcdsaSighashType::All),
-                |sighash_type| sighash_type.ecdsa_hash_ty(),
+                PsbtSighashType::ecdsa_hash_ty,
             )
     }
 
@@ -495,7 +495,7 @@ impl Input {
         self.sighash_type
             .map_or(
                 Some(SchnorrSighashType::Default),
-                |sighash_type| sighash_type.schnorr_hash_ty(),
+                PsbtSighashType::schnorr_hash_ty,
             )
     }
 

src/pset/mod.rs

@@ -296,12 +296,12 @@ impl PartiallySignedTransaction {
                     script_witness: psetin
                         .final_script_witness
                         .as_ref()
-                        .map(|x| x.to_owned())
+                        .map(Vec::to_owned)
                         .unwrap_or_default(),
                     pegin_witness: psetin
                         .pegin_witness
                         .as_ref()
-                        .map(|x| x.to_owned())
+                        .map(Vec::to_owned)
                         .unwrap_or_default(),
                 },
             };

src/sighash.rs

@@ -195,7 +195,7 @@ impl<T> Prevouts<'_, T> where T: Borrow<TxOut> {
             }
             Prevouts::All(prevouts) => prevouts
                 .get(input_index)
-                .map(|x| x.borrow())
+                .map(T::borrow)
                 .ok_or(Error::PrevoutIndex),
         }
     }

src/taproot.rs

@@ -571,7 +571,7 @@ impl TaprootMerkleBranch {
 
     /// Serialize self as bytes
     pub fn serialize(&self) -> Vec<u8> {
-        self.0.iter().flat_map(|e| e.as_byte_array()).copied().collect::<Vec<u8>>()
+        self.0.iter().flat_map(sha256::Hash::as_byte_array).copied().collect::<Vec<u8>>()
     }
 
     // Internal function to append elements to proof