Re-generate files again

tests/snapshots/output/header.snapshot.txt

@@ -11,7 +11,7 @@ fn main() {
         "The perimeter of the rectangle is {} pixels.",
         perimeter(&rect1)
     );
-    println!(r#"This line contains invalid utf8:  "øˆ€€€"#;
+    println!(r#"This line contains invalid utf8:  "�����"#;
 }
 
 fn area(rectangle: &Rectangle) -> u32 {