Issue: https://github.com/php/php-src/issues/10180
Author: tztztztz
### Description
Please, could you make mb_levenshtein function with multibyte support, so substituting for example
'a' with 'ą' would produce 1 instead of 2 in current non-multibyte levenshtein
function?
There are implementations of Levenshtein alghoritm in pure php that support multibyte characters,
but they are much slower that buit-in function written in C.
When you have to compare a word with whole dictionary containing millions of words it makes
significant difference.