Return value on PersistentMap.Builder.put even if entry already exists

Author: Abduqodiri Qurbonzoda

kotlinx-collections-immutable/src/main/kotlin/kotlinx/collections/immutable/implementations/immutableMap/TrieNode.kt

@@ -422,7 +422,10 @@ internal class TrieNode<K, V>(var dataMap: Int,
             val keyIndex = keyDataIndex(keyPosition)
 
             if (key == keyAtIndex(keyIndex)) {
-                if (valueAtKeyIndex(keyIndex) === value) { return this }
+                if (valueAtKeyIndex(keyIndex) === value) { // needs discussion
+                    mutator.operationResult = value
+                    return this
+                }
                 return mutableUpdateValueAtIndex(keyIndex, value, mutator)
             }
             mutator.size++