avcodec: Fix a doxy comment to refer to the right function

CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/avcodec.h

@@ -473,7 +473,7 @@ enum AVCodecID {
 /**
  * This struct describes the properties of a single codec described by an
  * AVCodecID.
- * @see avcodec_get_descriptor()
+ * @see avcodec_descriptor_get()
  */
 typedef struct AVCodecDescriptor {
     enum AVCodecID     id;