Improve the consistency between code and comments in Kotlin (#1268)

* style(kotlin): Make code and comments consistent.

* style(kotlin): convert comment location.

* style(c): Add missing comment.

* style(kotlin): Remove redundant semicolon, parenthesis and brace

* style(kotlin): Put constants inside the function.

* style(kotlin): fix unnecessary indentation.

* style(swift): Add missing comment.

* style(kotlin): Add missing comment.

* style(kotlin): Remove redundant comment.

* style(kotlin): Add missing comment.

* Update linked_list.kt

* style(csharp,js,ts): Add missing comment.

* style(kotlin): Remove empty lines.

* Update list.cs

* Update list.js

* Update list.ts

* roll back to commit 1

* style(cs,js,ts): Add missing comment in docfile.

* style(kotlin): Use normal element swapping instead of scope functions.

codes/kotlin/chapter_tree/binary_tree_bfs.kt

@@ -19,7 +19,7 @@ fun levelOrder(root: TreeNode?): MutableList<Int> {
     val list = mutableListOf<Int>()
     while (queue.isNotEmpty()) {
         val node = queue.poll()      // 队列出队
-        list.add(node?._val!!)      // 保存节点值
+        list.add(node?._val!!)       // 保存节点值
         if (node.left != null)
             queue.offer(node.left)   // 左子节点入队
         if (node.right != null)
@@ -31,7 +31,7 @@ fun levelOrder(root: TreeNode?): MutableList<Int> {
 /* Driver Code */
 fun main() {
     /* 初始化二叉树 */
-    // 这里借助了一个从数组直接生成二叉树的函数
+    // 这里借助了一个从列表直接生成二叉树的函数
     val root = TreeNode.listToTree(mutableListOf(1, 2, 3, 4, 5, 6, 7))
     println("\n初始化二叉树\n")
     printTree(root)