Function names do not support UTF-8/Unicode

[ulughann]

Functions or variable names do not support utf8 encoding instead relying on ascii via bytes in go.

eg.
local ğ = "hi"
is unusable as well as
funşi()

[cloudwindy]

I don't think the original Lua supports this. And using UTF-8 for function names is a very bad idea.

[baidwwy]

Like Lua official, add option?
https://github.com/lua/lua/blob/6baee9ef9d5657ab582c8a4b9f885ec58ed502d0/lctype.c#L20C14-L20C22