Improve comments

Author: Stypox

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeStreamInfoItemLockupExtractor.java

@@ -136,7 +136,7 @@ public String getName() throws ParsingException {
 
     @Override
     public long getDuration() throws ParsingException {
-        // Duration can not be extract from live streams, only from normal videos
+        // Duration cannot be extracted for live streams, but only for normal videos
         if (isLive()) {
             return -1;
         }

extractor/src/main/java/org/schabi/newpipe/extractor/stream/StreamInfoItemExtractor.java

@@ -56,9 +56,10 @@ public interface StreamInfoItemExtractor extends InfoItemExtractor {
     long getDuration() throws ParsingException;
 
     /**
-     * Parses the number of views
+     * Parses the number of views (or of current viewers in case of live streams)
      *
-     * @return the number of views or -1 if not available
+     * @return the number of views (or of current viewers in case of live streams) or -1 if not
+     * available
      * @throws ParsingException if there is an error in the extraction
      */
     long getViewCount() throws ParsingException;