The font previews only show latin text

[hughsie]

We should show the language supported by the font, e.g. rpm -q --provides lohit-assamese-fonts
config(lohit-assamese-fonts) = 2.5.3-2.fc20
font(:lang=as)
font(:lang=bn)
font(:lang=mni)
font(lohitassamese)
lohit-assamese-fonts = 2.5.3-2.fc20

So, show অসমীয়া for "as".