doc/filters: reword vidstab options intro.

doc/filters.texi

@@ -5323,8 +5323,7 @@ the unsharp filter, see below.
 To enable compilation of this filter you need to configure FFmpeg with
 @code{--enable-libvidstab}.
 
-This filter accepts the following named options, expressed as a
-sequence of @var{key}=@var{value} pairs, separated by ":".
+This filter accepts the following options:
 
 @table @option
 
@@ -5853,8 +5852,7 @@ rotation about subsequent frames.
 To enable compilation of this filter you need to configure FFmpeg with
 @code{--enable-libvidstab}.
 
-This filter accepts the following named options, expressed as a
-sequence of @var{key}=@var{value} pairs, separated by ":".
+This filter accepts the following options:
 
 @table @option
 @item result