feat: Cyrillic and Greek support

[lsimeonov]

Added support for Greek and Cyrillic unicodes

This is done by tracking the byte count and correctly handling the multibyte strings

Added simple test for this

[zhengchun]

Why should we need add this new condition for cyrillic and greek. We already knows Non-English letters yet.

[zhengchun]

Thanks for your work. I have some question about this code:

unicode.Is(cyrillic, r) || unicode.Is(greek, r)

Why should we need this condition. Removing this code still can works, I test now supports Non-English like Chinese or another language now.

Thanks again.

[lsimeonov]

Good catch. That was a leftover test from removed code. The idea was to allow certain charsets, but it’s better left to the user to decide post-parsing.

I removed the change