Syriac diacritics
Fragment of a discussion from User talk:Rua
It is definitely the right character U+0308. I tested it to make sure, and u(0x0308)
produces the same character that is in the Syriac word above.
There is probably a bug in Lua's regex implementation. I moved the combining diaeresis to the beginning of the bracket block and now it works. I tested it and it doesn't work in any other position.