WW: baraga -> brag

WW currently transliterates [b][r][g] as brag, which is
definitely wrong. Probably the fix is to say that b
cannot prefix r unless r has a subscript (maybe
specifically unless it has an l subscript --
grammarians differ).

That's easy enough, but thought needs to be given as to
whether there is not some larger class of such
problems, in which a non-Tibetan word transliterates as
a Tibetan one, even when the grammar is correct.