[css-text] animatibility of 'tab-size'

Currently css-text says that 'tab-size' is animatable as a length,
but not as an integer.  This seems odd, given that it takes both
length and integer values.  Is there a reason for this?

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                          https://www.mozilla.org/   𝄂
             Before I built a wall I'd ask to know
             What I was walling in or walling out,
             And to whom I was like to give offense.
               - Robert Frost, Mending Wall (1914)