update snapshot tests

tests/snapshots/output/changes_header_numbers.snapshot.txt

@@ -1,23 +1,24 @@
        File: sample.rs
-   1   struct Rectangle {
-   2       width: u32,
-   3       height: u32,
-   4   }
-   5   
-   6 _ fn main() {
-   7       let rect1 = Rectangle { width: 30, height: 50 };
-   8   
-   9       println!(
-  10 ~         "The perimeter of the rectangle is {} pixels.",
-  11 ~         perimeter(&rect1)
-  12       );
-  13 +     println!(r#"This line contains invalid utf8:  "<22><><EFBFBD><EFBFBD><EFBFBD>"#;
-  14   }
-  15   
-  16   fn area(rectangle: &Rectangle) -> u32 {
-  17       rectangle.width * rectangle.height
-  18   }
-  19 + 
-  20 + fn perimeter(rectangle: &Rectangle) -> u32 {
-  21 +     (rectangle.width + rectangle.height) * 2
-  22 + }
+   1 + /// A rectangle. First line is changed to prevent a regression of #1869
+   2   struct Rectangle {
+   3       width: u32,
+   4       height: u32,
+   5   }
+   6   
+   7 _ fn main() {
+   8       let rect1 = Rectangle { width: 30, height: 50 };
+   9   
+  10       println!(
+  11 ~         "The perimeter of the rectangle is {} pixels.",
+  12 ~         perimeter(&rect1)
+  13       );
+  14 +     println!(r#"This line contains invalid utf8:  "<22><><EFBFBD><EFBFBD><EFBFBD>"#;
+  15   }
+  16   
+  17   fn area(rectangle: &Rectangle) -> u32 {
+  18       rectangle.width * rectangle.height
+  19   }
+  20 + 
+  21 + fn perimeter(rectangle: &Rectangle) -> u32 {
+  22 +     (rectangle.width + rectangle.height) * 2
+  23 + }