Fuzzy Levenshtein variant of std.conv.to

[via Digitalmars-d-learn]

At

https://github.com/nordlow/justd/blob/master/conv_ex.d

I'm trying to figure out how to best implement a fuzzy variant of 
std.conv.to when converting a string to an enum.

I'm almost there but I'm uncertain how to best pick the index of 
the smallest element in `distances` and then convert it to the 
corresponding enumerator for when `U` is an enum.

Help please.