Bug 70509 - Candrabindu+Visarga doesn't work in Devanagari
https://bugs.freedesktop.org/show_bug.cgi?id=70509
We categorize both bindus and visarga as syllable-modifiers.
OT spec doesn't actually say what characters go in the syllable
modifier category, and allows one. We just allow up to two now.
Test case: U+0930,U+0941,U+0901,U+0903
Uniscribe currently doesn't support that and produces a
dotted circle.
The spec says: "[{M}+[N]+[H]]", and that's what Uniscribe implements.
We instead do: "{M+[N]+[H]}", which means we allow Nukta and Halant
after all Matras, not just the last one. It makes more sense.
In the case of Consonant,LeftMatra,Halant, Uniscribe leaves the Halant
where it is, but we want to move it with the Matra as that makes more
logical sense.
Behdad Esfahbod