[css3-fonts] 'font-size-adjust' and 'font-size':<percentage> should treat negative values as an error

http://www.w3.org/TR/css3-fonts/#font-size-adjust-prop should say
that 'font-size-adjust' treats negative values as a parsing error,
just like 'font-size' does.

'font-size' should also say that negative <percentage> values are
illegal, like it says for negative <length> values.  (This error is
not present in CSS 2.1.)

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/