Remove unneeded pub

exercises/15_traits/traits3.rs

@@ -3,7 +3,7 @@
 //
 // Consider what you can add to the Licensed trait.
 
-pub trait Licensed {
+trait Licensed {
     fn licensing_info(&self) -> String;
 }
 

exercises/15_traits/traits4.rs

@@ -2,7 +2,7 @@
 //
 // Don't change any line other than the marked one.
 
-pub trait Licensed {
+trait Licensed {
     fn licensing_info(&self) -> String {
         "some information".to_string()
     }

exercises/15_traits/traits5.rs

@@ -2,13 +2,13 @@
 //
 // Don't change any line other than the marked one.
 
-pub trait SomeTrait {
+trait SomeTrait {
     fn some_function(&self) -> bool {
         true
     }
 }
 
-pub trait OtherTrait {
+trait OtherTrait {
     fn other_function(&self) -> bool {
         true
     }