Diacritics panic

[zaaarf]

On version 6.0.0, I have encountered a panic at line 238, column 26, with error: byte index 2 is not a char boundary; it is inside 'ã' (bytes 1..3) of 'São Tomé e Príncipe'.

The problem appears to be the diacritic. I think it doesn't support Unicode characters at all.

I'll see if i can get a PR for fixing this done soon.

edit: the underlying find library provides you with the char index, not a byte index. The problem is that you treat that as a byte index.

[zaaarf]

Opened a PR. You can probably make my implementation a bit more elegant, but it works.