cosmetics: spelling typo fixes

Originally committed as revision 13489 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h263.c

@@ -5728,7 +5728,7 @@ static int decode_vol_header(MpegEncContext *s, GetBitContext *gb){
 
 /**
  * decodes the user data stuff in the header.
- * allso inits divx/xvid/lavc_version/build
+ * Also initializes divx/xvid/lavc_version/build.
  */
 static int decode_user_data(MpegEncContext *s, GetBitContext *gb){
     char buf[256];

libavcodec/h264.c

@@ -3851,7 +3851,7 @@ static void clone_slice(H264Context *dst, H264Context *src)
 
 /**
  * decodes a slice header.
- * this will allso call MPV_common_init() and frame_start() as needed
+ * This will also call MPV_common_init() and frame_start() as needed.
  *
  * @param h h264context
  * @param h0 h264 master context (differs from 'h' when doing sliced based parallel decoding)