style: format code and docs with prettier

Author: yanglbme

lcof/面试题56 - I. 数组中数字出现的次数/README.md

@@ -210,15 +210,15 @@ class Solution {
         for num in nums {
             xorSum ^= num
         }
-        
+
         let lowBit = xorSum & -xorSum
         var a = 0
         for num in nums {
             if (num & lowBit) != 0 {
                 a ^= num
             }
         }
-        
+
         let b = xorSum ^ a
         return [a, b]
     }