Update E0478.md

Author: Dylan-DPC

src/librustc_error_codes/error_codes/E0478.md

@@ -21,8 +21,8 @@ this issue, you need to specify it:
 ```
 trait Wedding<'t>: 't { }
 
-struct Prince<'kiss, 'SnowWhite: 'kiss> { // You say here that 'SnowWhite must live
-                                          // longer than 'kiss.
+struct Prince<'kiss, 'SnowWhite: 'kiss> { // You say here that 'SnowWhite
+                                          // must live longer than 'kiss.
     child: Box<Wedding<'kiss> + 'SnowWhite>, // And now it's all good!
 }
 ```