Removed trailing whitespace in hw1/task4

hw1/task4/src/lib.rs

 pub fn sum_of_squares(n: i32) -> i32 {
     let mut i: i32 = 0;
     for x in 1..n+1 {
-       i += x.pow(2); 
+       i += x.pow(2);
     }
     i
 }