style: format code and docs with prettier

Author: yanglbme

lcof2/剑指 Offer II 104. 排列的数目/README.md

@@ -143,12 +143,12 @@ func combinationSum4(nums []int, target int) int {
 
 #### Swift
 
-```swift 
+```swift
 class Solution {
     func combinationSum4(_ nums: [Int], _ target: Int) -> Int {
         var dp = [Int](repeating: 0, count: target + 1)
         dp[0] = 1
-        
+
         for i in 1...target {
             for num in nums {
                 if i >= num, dp[i] <= Int.max - dp[i - num] {