Let clippy fix

tests/feed_validation.rs

@@ -18,7 +18,7 @@ fn test_if_feeds_are_in_alphabetical_order() {
         urls.sort();
 
         for url in urls {
-            println!("{}", url);
+            println!("{url}");
         }
         panic!("feeds.txt was not sorted!")
     }
@@ -50,7 +50,7 @@ fn test_if_duplicates_in_feeds_list() {
 
     if !duplicates.is_empty() {
         for dupe in duplicates {
-            println!("{}", dupe)
+            println!("{dupe}")
         }
         panic!("Duplicate entries found!")
     }