[css-fonts-3] i18n-ISSUE-294: Fonts available on platforms

4.1. The @font-face rule
http://www.w3.org/TR/2013/WD-css-fonts-3-20130711/#font-face-rule


Editorial nit

nit: "rather than limiting the font choice to a set of fonts available 
on all platforms" -> "rather than limiting the font choice to a set of 
fonts available on the user's platform"


(not discussed with i18n WG)