refactor: Replace 结点 with 节点 (#452)

* Replace 结点 with 节点
Update the footnotes in the figures

* Update mindmap

* Reduce the size of the mindmap.png

codes/javascript/modules/TreeNode.js

@@ -8,10 +8,10 @@
  * Definition for a binary tree node.
  */
 class TreeNode {
-    val; // 结点值
-    left; // 左子结点指针
-    right; // 右子结点指针
-    height; //结点高度
+    val; // 节点值
+    left; // 左子节点指针
+    right; // 右子节点指针
+    height; //节点高度
     constructor(val, left, right, height) {
         this.val = val === undefined ? 0 : val;
         this.left = left === undefined ? null : left;