Correct formatting.

2018/src/day13.rs

@@ -83,7 +83,6 @@ impl PartialOrd for Cart {
     }
 }
 
-
 #[derive(Default)]
 pub struct Day13 {
     grid: Vec<Vec<char>>,
@@ -230,7 +229,6 @@ mod tests {
         assert_eq!("7,3", instance.part1(&mut SAMPLE1_INPUT))
     }
 
-
     #[test]
     fn sample_part2() {
         let mut instance = Day13::new();