Make function comment a bit more linguistically correct.

Originally committed as revision 15835 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rdt.h

@@ -73,7 +73,7 @@ void ff_rdt_subscribe_rule2(RDTDemuxContext *s, char *cmd, int size,
  * @param buf input buffer
  * @param len length of input buffer
  * @param set_id will be set to the set ID this packet belongs to
- * @param seq_no will be set to the sequence number this packet belongs to
+ * @param seq_no will be set to the sequence number of the packet
  * @param stream_id will be set to the stream ID this packet belongs to
  * @param is_keyframe will be whether this packet belongs to a keyframe
  * @param timestamp will be set to the timestamp of the packet