[youtube:channel] Specify first page download message

youtube_dl/extractor/youtube.py

@@ -1388,7 +1388,7 @@ class YoutubeChannelIE(InfoExtractor):
         channel_id = self._match_id(url)
 
         url = self._TEMPLATE_URL % channel_id
-        channel_page = self._download_webpage(url, channel_id)
+        channel_page = self._download_webpage(url, channel_id, 'Downloading page #1')
         autogenerated = re.search(r'''(?x)
                 class="[^"]*?(?:
                     channel-header-autogenerated-label|