Merge #390: Add the equivalent of ForEach::as_key() for PkPkh

9570d49 Add the equivalent of `ForEach::as_key()` for `PkPkh` (Alekos Filini)

Pull request description:

ACKs for top commit:
  apoelstra:
    ACK 9570d49
  sanket1729:
    ACK 9570d49

Tree-SHA512: 8e82578b09d6d5c7016f0da3bb7b5f34807233e96e022899a6409276fe60801c35ba05da655cc6d0f27c688afda8add9fe31c72a6304da0849ad5225cfb0c177

Author: sanket1729

src/miniscript/iter.rs

@@ -368,6 +368,16 @@ pub enum PkPkh<Pk: MiniscriptKey> {
     HashedPubkey(Pk::Hash),
 }
 
+impl<Pk: MiniscriptKey<Hash = Pk>> PkPkh<Pk> {
+    /// Convenience method to avoid distinguishing between keys and hashes when these are the same type
+    pub fn as_key(self) -> Pk {
+        match self {
+            PkPkh::PlainPubkey(pk) => pk,
+            PkPkh::HashedPubkey(pkh) => pkh,
+        }
+    }
+}
+
 /// Iterator for traversing all [MiniscriptKey]'s and hashes, depending what data are present in AST,
 /// starting from some specific node which constructs the iterator via
 /// [Miniscript::iter_pk_pkh] method.