fix(model-datastructure): implement IKVEntryReference.toString

Author: slisson

model-datastructure/src/commonMain/kotlin/org/modelix/model/lazy/NonWrittenEntry.kt

@@ -37,4 +37,8 @@ class NonWrittenEntry<E : IKVValue> : IKVEntryReference<E> {
             deserialized.isWritten = true
         }
     }
+
+    override fun toString(): String {
+        return hash
+    }
 }

model-datastructure/src/commonMain/kotlin/org/modelix/model/lazy/WrittenEntry.kt

@@ -30,4 +30,8 @@ class WrittenEntry<E : IKVValue>(
     override fun write(store: IDeserializingKeyValueStore) {}
 
     override fun getDeserializer(): (String) -> E = deserializer
+
+    override fun toString(): String {
+        return hash
+    }
 }