qualify call to std::str::from_utf8
qualify call to std::str::from_utf8

the call needs to be qualified in the macro expansion, or else
callers will get errors if they don't have
`use std::str::from_utf8`
in their code.

meh/nom,pwoolcoc/nom,Keruspe/nom,Geal/nom,sourrust/nom,AndyShiue/nom