[mgtv] Extract format_note (#21881)

format_note should now show 标清, 高清, 超清, 蓝光, etc.

youtube_dl/extractor/mgtv.py

@@ -82,6 +82,7 @@ def _real_extract(self, url):
                 'http_headers': {
                     'Referer': url,
                 },
+                'format_note': stream.get('name'),
             })
         self._sort_formats(formats)