Add APIchanges entry after r25227.

Originally committed as revision 25228 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/APIchanges

@@ -13,6 +13,10 @@ libavutil:   2009-03-08
 
 API changes, most recent first:
 
+2010-09-27 - r25227 - lavfi 1.47.0 - AVFilterLink
+  Make the AVFilterLink fields srcpad and dstpad store the pointers to
+  the source and destination pads, rather than their indexes.
+
 2010-09-27 - r25225 - lavu 50.30.0 - av_get_token()
   Move av_get_token() from libavfilter/parseutils.h to
   libavutil/avstring.h.