Be more verbose in describing VQF demuxer

Originally committed as revision 17879 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/general.texi

@@ -211,7 +211,8 @@ library:
     @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
 @item True Audio                @tab   @tab X
 @item VC-1 test bitstream       @tab X @tab X
-@item VQF                       @tab   @tab X
+@item NTT TwinVQ (VQF)          @tab   @tab X
+    @tab Nippon Telegraph and Telephone Corporation TwinVQ.
 @item WAV                       @tab X @tab X
 @item WavPack                   @tab   @tab X
 @item Wing Commander III movie  @tab   @tab X