fix(structs3): remove redundant 'return' (#852)

Author: EmisonLu

exercises/structs/structs3.rs

@@ -18,11 +18,11 @@ impl Package {
         if weight_in_grams <= 0 {
             // Something goes here...
         } else {
-            return Package {
+            Package {
                 sender_country,
                 recipient_country,
                 weight_in_grams,
-            };
+            }
         }
     }