doc/general: mention WSD demuxer

Signed-off-by: Paul B Mahol <onemda@gmail.com>

doc/general.texi

@@ -520,6 +520,7 @@ library:
     @tab Multimedia format used in Westwood Studios games.
 @item Westwood Studios VQA      @tab   @tab X
     @tab Multimedia format used in Westwood Studios games.
+@item Wideband Single-bit Data (WSD) @tab   @tab X
 @item WVE                       @tab   @tab X
 @item XMV                       @tab   @tab X
     @tab Microsoft video container used in Xbox games.