lavc: turn mentions of AV_CODEC_FLAG_RECON_FRAME in doxy into links

libavcodec/avcodec.h

@@ -2665,7 +2665,7 @@ int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);
 
 /**
  * Return decoded output data from a decoder or encoder (when the
- * AV_CODEC_FLAG_RECON_FRAME flag is used).
+ * @ref AV_CODEC_FLAG_RECON_FRAME flag is used).
  *
  * @param avctx codec context
  * @param frame This will be set to a reference-counted video or audio
@@ -2679,7 +2679,7 @@ int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);
  * @retval AVERROR_EOF      the codec has been fully flushed, and there will be
  *                          no more output frames
  * @retval AVERROR(EINVAL)  codec not opened, or it is an encoder without the
- *                          AV_CODEC_FLAG_RECON_FRAME flag enabled
+ *                          @ref AV_CODEC_FLAG_RECON_FRAME flag enabled
  * @retval AVERROR_INPUT_CHANGED current decoded frame has changed parameters with
  *                          respect to first decoded frame. Applicable when flag
  *                          AV_CODEC_FLAG_DROPCHANGED is set.