fix href in example

spec.asciidoc

@@ -116,7 +116,7 @@ Here is an example:
       </bookmark>
       <folder>
         <title>Information</title>
-        <bookmark href="http://radioexample.com/shows/learn-cook">
+        <bookmark href="http://radioexample.com/shows/uncensored">
           <title>Uncensored information</title>
           <info>
             <metadata owner="https://radiomanifest.degenerazione.xyz/">