Update 0977.有序数组的平方.md

add rust  highlighting

problems/0977.有序数组的平方.md

@@ -179,7 +179,7 @@ func sortedSquares(nums []int) []int {
 }
 ```
 Rust
-```
+```rust
 impl Solution {
     pub fn sorted_squares(nums: Vec<i32>) -> Vec<i32> {
         let n = nums.len();