[cssom] small typo in cssom, and minor wording issue

One of these paragraphs is not like the others; it has a few extra
words and is missing a link.  The attached patch should fix, I
think.

I'm also a little confused by the words "with as value the" in all 4
paragraphs in this section.  I think they make the sentence fail to
parse as valid English, but I'm not quite sure what was intended.
Perhaps "with the value being"?

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂