avcodec: clarify the CODEC_CAP_DELAY note in avcodec_decode_video2()

libavcodec/avcodec.h

@@ -3865,8 +3865,9 @@ int avcodec_decode_audio3(AVCodecContext *avctx, int16_t *samples,
  *
  * In practice, avpkt->data should have 4 byte alignment at minimum.
  *
- * @note Some codecs have a delay between input and output, these need to be
- * fed with avpkt->data=NULL, avpkt->size=0 at the end to return the remaining frames.
+ * @note Codecs which have the CODEC_CAP_DELAY capability set have a delay
+ * between input and output, these need to be fed with avpkt->data=NULL,
+ * avpkt->size=0 at the end to return the remaining frames.
  *
  * @param avctx the codec context
  * @param[out] picture The AVFrame in which the decoded video frame will be stored.