Replace uses of encode_to_engine with encode_to_hash

diff --git a/bitcoin/src/crypto/sighash.rs b/bitcoin/src/crypto/sighash.rs
index c2db1a38..ee063131 100644
--- a/bitcoin/src/crypto/sighash.rs
+++ b/bitcoin/src/crypto/sighash.rs
@@ -450,7 +450,6 @@ impl<R: Borrow<Transaction>> SighashCache<R> {
         // If hash_type & 3 equals SIGHASH_SINGLE:
         //      sha_single_output (32): the SHA256 of the corresponding output in CTxOut format.
         if sighash == TapSighashType::Single {
-            let mut enc = sha256::Hash::engine();
             let txout = self
                 .tx
                 .borrow()
@@ -461,8 +460,7 @@ impl<R: Borrow<Transaction>> SighashCache<R> {
                     outputs_length: self.tx.borrow().outputs.len(),
                 }))
                 .map_err(SigningDataError::Sighash)?;
-            hashes::encode_to_engine(txout, &mut enc);
-            let hash = sha256::Hash::from_engine(enc);
+            let hash = hashes::encode_to_hash::<_, sha256::HashEngine>(txout);
             writer.write_all(&hash.to_byte_array())?;
         }
 
diff --git a/primitives/src/block.rs b/primitives/src/block.rs
index 4910bc37..c917da06 100644
--- a/primitives/src/block.rs
+++ b/primitives/src/block.rs
@@ -16,7 +16,9 @@ use arbitrary::{Arbitrary, Unstructured};
 use encoding::{ArrayDecoder, Decoder6};
 #[cfg(feature = "alloc")]
 use encoding::{CompactSizeEncoder, Decoder2, Encoder2, SliceEncoder, VecDecoder};
-use hashes::{sha256d, HashEngine as _};
+use hashes::sha256d;
+#[cfg(feature = "alloc")]
+use hashes::HashEngine as _;
 
 #[cfg(feature = "hex")]
 use crate::hex_codec::HexPrimitive;
@@ -465,9 +467,8 @@ impl Header {
     /// Returns the block hash.
     // This is the same as `Encodable` but done manually because `Encodable` isn't in `primitives`.
     pub fn block_hash(&self) -> BlockHash {
-        let mut engine = sha256d::Hash::engine();
-        hashes::encode_to_engine(self, &mut engine);
-        BlockHash::from_byte_array(engine.finalize().to_byte_array())
+        let hash = hashes::encode_to_hash::<_, sha256d::HashEngine>(self);
+        BlockHash::from_byte_array(hash.to_byte_array())
     }
 }