feat: update ts solution to lc problem: No.0104 (#1424)

Author: thinkasany

solution/0100-0199/0104.Maximum Depth of Binary Tree/README.md

@@ -194,7 +194,7 @@ var maxDepth = function (root) {
  */
 
 function maxDepth(root: TreeNode | null): number {
-    if (root == null) {
+    if (root === null) {
         return 0;
     }
     return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));

solution/0100-0199/0104.Maximum Depth of Binary Tree/README_EN.md

@@ -174,7 +174,7 @@ var maxDepth = function (root) {
  */
 
 function maxDepth(root: TreeNode | null): number {
-    if (root == null) {
+    if (root === null) {
         return 0;
     }
     return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));

solution/0100-0199/0104.Maximum Depth of Binary Tree/Solution.ts

@@ -13,7 +13,7 @@
  */
 
 function maxDepth(root: TreeNode | null): number {
-    if (root == null) {
+    if (root === null) {
         return 0;
     }
     return 1 + Math.max(maxDepth(root.left), maxDepth(root.right));