AK: Fix URL's operator<<() and use it

Author: https://github.com/linusg
Commit: ad3871b64e
Pull-request: https://github.com/SerenityOS/serenity/pull/2253
Issue: https://github.com/SerenityOS/serenity/issues/2250

AK/URL.h

@@ -89,11 +89,9 @@ private:
     String m_data_payload;
 };
 
-}
-
-using AK::URL;
-
 inline const LogStream& operator<<(const LogStream& stream, const URL& value)
 {
     return stream << value.to_string();
 }
+
+}