Merge rust-bitcoin/rust-bitcoin#2227: add conversions from TXIDs to merkle nodes

32eb461523 add conversions from TXIDs to merkle nodes (conduition)

Pull request description:

  Fixes https://github.com/rust-bitcoin/rust-bitcoin/issues/2220.

  Also adds the equivalent conversion trait from `Wtxid` -> `WitnessMerkleNode`.

ACKs for top commit:
  Kixunil:
    ACK 32eb461523
  apoelstra:
    ACK 32eb461523

Tree-SHA512: 61cf5548874388dd927feaa50f3c7c7e9f3ac4f7498f6335835499dec93916b5f7ed2bdf91ec27edc977fb5e811f946364d477d4aa25d0aa51b0c618f727d3d2

bitcoin/src/hash_types.rs

@@ -94,4 +94,16 @@ mod newtypes {
 
     impl_hashencode!(FilterHash);
     impl_hashencode!(FilterHeader);
+
+    impl From<Txid> for TxMerkleNode {
+        fn from(txid: Txid) -> Self {
+            Self::from(txid.0)
+        }
+    }
+
+    impl From<Wtxid> for WitnessMerkleNode {
+        fn from(wtxid: Wtxid) -> Self {
+            Self::from(wtxid.0)
+        }
+    }
 }