Reformat documentation for -vsync @var{parameter}.

Make use of "@table @option" for showing the valid values for the
option.

Originally committed as revision 26385 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/ffmpeg.texi

@@ -670,16 +670,25 @@ Repeatedly loop output for formats that support looping such as animated GIF
 Thread count.
 @item -vsync @var{parameter}
 Video sync method.
-0   Each frame is passed with its timestamp from the demuxer to the muxer
-1   Frames will be duplicated and dropped to achieve exactly the requested
-    constant framerate.
-2   Frames are passed through with their timestamp or dropped so as to prevent
-    2 frames from having the same timestamp
--1  Chooses between 1 and 2 depending on muxer capabilities. This is the default method.
 
-With -map you can select from
-which stream the timestamps should be taken. You can leave either video or
-audio unchanged and sync the remaining stream(s) to the unchanged one.
+@table @option
+@item 0
+Each frame is passed with its timestamp from the demuxer to the muxer.
+@item 1
+Frames will be duplicated and dropped to achieve exactly the requested
+constant framerate.
+@item 2
+Frames are passed through with their timestamp or dropped so as to
+prevent 2 frames from having the same timestamp.
+@item -1
+Chooses between 1 and 2 depending on muxer capabilities. This is the
+default method.
+@end table
+
+With -map you can select from which stream the timestamps should be
+taken. You can leave either video or audio unchanged and sync the
+remaining stream(s) to the unchanged one.
+
 @item -async @var{samples_per_second}
 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
 the parameter is the maximum samples per second by which the audio is changed.