remove test results in extractor modules

and add generic example URLs

gallery_dl/extractor/ytdl.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2021-2022 Mike Fährmann
+# Copyright 2021-2023 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -19,7 +19,7 @@ class YoutubeDLExtractor(Extractor):
     filename_fmt = "{title}-{id}.{extension}"
     archive_fmt = "{extractor_key} {id}"
     pattern = r"ytdl:(.*)"
-    test = ("ytdl:https://www.youtube.com/watch?v=BaW_jenozKc&t=1s&end=9",)
+    example = "ytdl:https://www.youtube.com/watch?v=abcdefghijk"
 
     def __init__(self, match):
         # import main youtube_dl module