Update js code style in space_time_tradeoff.md

docs/chapter_computational_complexity/space_time_tradeoff.md

@@ -204,16 +204,16 @@ comments: true
 
     ```js title="leetcode_two_sum.js"
     function twoSumHashTable(nums, target) {
-      // 辅助哈希表，空间复杂度 O(n)
-      let m = {}
-      // 单层循环，时间复杂度 O(n)
-      for (let i = 0; i < nums.length; i++) {
-        if (m[nums[i]] !== undefined) {
-          return [m[nums[i]], i]
-        } else {
-          m[target - nums[i]] = i;
+        // 辅助哈希表，空间复杂度 O(n)
+        let m = {}
+        // 单层循环，时间复杂度 O(n)
+        for (let i = 0; i < nums.length; i++) {
+            if (m[nums[i]] !== undefined) {
+                return [m[nums[i]], i]
+            } else {
+                m[target - nums[i]] = i;
+            }
         }
-      }
     }
     ```