[bilibili] warn when target URL is a playlist

src/you_get/extractors/bilibili.py

@@ -167,8 +167,8 @@ class Bilibili(VideoExtractor):
             qq_download_by_vid(tc_flashvars, self.title, output_dir=kwargs['output_dir'], merge=kwargs['merge'], info_only=kwargs['info_only'])
             return
 
-        has_plist = re.search(r'<option', self.page)
-        if has_plist and r1('index_(\d+).html', self.url) is None:
+        has_plist = re.search(r'"page":2', self.page)
+        if has_plist:
             log.w('This page contains a playlist. (use --playlist to download all videos.)')
 
         try: