update 优化Python语法高亮显示

problems/0042.接雨水.md

@@ -471,7 +471,7 @@ class Solution {
 ### Python:
 
 双指针法
-```python3
+```Python
 class Solution:
     def trap(self, height: List[int]) -> int:
         res = 0
@@ -510,7 +510,7 @@ class Solution:
         return result
 ```
 单调栈
-```python3
+```Python
 class Solution:
     def trap(self, height: List[int]) -> int:
         # 单调栈

problems/0257.二叉树的所有路径.md

@@ -468,7 +468,7 @@ class Solution {
 ---
 ## Python:  
 递归法+隐形回溯
-```Python3
+```Python
 # Definition for a binary tree node.
 # class TreeNode:
 #     def __init__(self, val=0, left=None, right=None):
@@ -499,7 +499,7 @@ class Solution:
 
 迭代法：
 
-```python3
+```Python
 from collections import deque
 
 

problems/前序/ACM模式如何构建二叉树.md

@@ -280,7 +280,7 @@ public class Solution {
 
 ## Python 
 
-```Python3
+```Python
 class TreeNode:
     def __init__(self, val = 0, left = None, right = None):
         self.val = val