Use "bytes" instead of "characters" consistently when talking about length of a String.

exercises/05_ticket_v2/03_variants_with_data/src/lib.rs

@@ -22,13 +22,13 @@ impl Ticket {
             panic!("Title cannot be empty");
         }
         if title.len() > 50 {
-            panic!("Title cannot be longer than 50 characters");
+            panic!("Title cannot be longer than 50 bytes");
         }
         if description.is_empty() {
             panic!("Description cannot be empty");
         }
         if description.len() > 500 {
-            panic!("Description cannot be longer than 500 characters");
+            panic!("Description cannot be longer than 500 bytes");
         }
 
         Ticket {