feat: add javascript solution to lcci problem: No.02.02.Kth Node From End of List (doocs#367)

* feat: add javascript solution to lcci problem: No.02.01.Remove Duplicate Node

* feat: add javascript solution to lcci problem: No.02.02.Kth Node From End of List

Author: zhaocchen

lcci/02.01.Remove Duplicate Node/README.md

@@ -104,7 +104,7 @@ class Solution {
 
 ### **JavaScript**
 
-```javascript
+```js
 /**
  * Definition for singly-linked list.
  * function ListNode(val) {

lcci/02.01.Remove Duplicate Node/README_EN.md

@@ -105,7 +105,7 @@ class Solution {
 
 ### **JavaScript**
 
-```javascript
+```js
 /**
  * Definition for singly-linked list.
  * function ListNode(val) {

lcci/02.02.Kth Node From End of List/README.md

@@ -77,6 +77,34 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @param {number} k
+ * @return {number}
+ */
+var kthToLast = function(head, k) {
+    let fast = head, slow = head;
+    for (let i = 0; i < k; i++) {
+        fast = fast.next;
+    }
+    while (fast != null) {
+        fast = fast.next;
+        slow = slow.next;
+    }
+    return slow.val;
+};
+```
+
 ### **...**
 
 ```

lcci/02.02.Kth Node From End of List/README_EN.md

@@ -69,6 +69,34 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @param {number} k
+ * @return {number}
+ */
+var kthToLast = function(head, k) {
+    let fast = head, slow = head;
+    for (let i = 0; i < k; i++) {
+        fast = fast.next;
+    }
+    while (fast != null) {
+        fast = fast.next;
+        slow = slow.next;
+    }
+    return slow.val;
+};
+```
+
 ### **...**
 
 ```

lcci/02.02.Kth Node From End of List/Solution.js

@@ -0,0 +1,23 @@
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val) {
+ *     this.val = val;
+ *     this.next = null;
+ * }
+ */
+/**
+ * @param {ListNode} head
+ * @param {number} k
+ * @return {number}
+ */
+ var kthToLast = function(head, k) {
+    let fast = head, slow = head;
+    for (let i = 0; i < k; i++) {
+        fast = fast.next;
+    }
+    while (fast != null) {
+        fast = fast.next;
+        slow = slow.next;
+    }
+    return slow.val;
+};