Add kotlin code for the chapter of tree (#1172)

* modified array.kt.

* feat(kotlin): add kotlin code for the chapter of stack and queue.

* modified array.kt

* modified comments.

* feat(kotlin): add kotlin code for the chapter of tree.

* feat(kotlin): add kotlin code for the chapter of tree.

codes/kotlin/chapter_tree/binary_tree.kt

@@ -0,0 +1,40 @@
+/**
+ * File: binary_tree.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_tree
+
+import utils.TreeNode
+import utils.printTree
+
+/* Driver Code */
+fun main() {
+    /* 初始化二叉树 */
+    // 初始化节点
+    val n1 = TreeNode(1)
+    val n2 = TreeNode(2)
+    val n3 = TreeNode(3)
+    val n4 = TreeNode(4)
+    val n5 = TreeNode(5)
+    // 构建节点之间的引用（指针）
+    n1.left = n2
+    n1.right = n3
+    n2.left = n4
+    n2.right = n5
+    println("\n初始化二叉树\n")
+    printTree(n1)
+
+    /* 插入与删除节点 */
+    val P = TreeNode(0)
+    // 在 n1 -> n2 中间插入节点 P
+    n1.left = P
+    P.left = n2
+    println("\n插入节点 P 后\n")
+    printTree(n1)
+    // 删除节点 P
+    n1.left = n2
+    println("\n删除节点 P 后\n")
+    printTree(n1)
+}