Update subtitle tests comments

Author: TobiGr

extractor/src/test/java/org/schabi/newpipe/extractor/services/youtube/stream/YoutubeStreamExtractorControversialTest.java

@@ -122,13 +122,13 @@ public void testGetVideoStreams() throws IOException, ExtractionException {
 
     @Test
     public void testGetSubtitlesListDefault() throws IOException, ExtractionException {
-        // Video (/view?v=YQHsXMglC9A) set in the setUp() method has no captions => null
+        // Video (/view?v=T4XJQO3qol8) set in the setUp() method has at least auto-generated (English) captions
         assertFalse(extractor.getSubtitlesDefault().isEmpty());
     }
 
     @Test
     public void testGetSubtitlesList() throws IOException, ExtractionException {
-        // Video (/view?v=YQHsXMglC9A) set in the setUp() method has no captions => null
+        // Video (/view?v=T4XJQO3qol8) set in the setUp() method has at least auto-generated (English) captions
         assertFalse(extractor.getSubtitles(MediaFormat.TTML).isEmpty());
     }
 }