support multi-byte strings on Windows

[mattn]

On Windows, it use double-byte character sets not UTF-8. So ReadFile return DBCS bytes. it should be converted to UTF-8.

[muesli]

Hey @mattn!

Nice seeing you over here! Your contribution looks great, but I'm a bit puzzled about the go fmt changes. I can't reproduce that output locally, neither with go fmt nor with goimports or goreturns. What tool did you use to format the sources?

If you don't mind, I could revert the formatting changes, so we can focus on reviewing the actual change.

Thanks again!

[mattn]

Ah, it seems that specification of go fmt changes recently. Sorry. I'll update this PR soon.

[mattn]

Hmm, at least, same result in go1.18.

[mattn]

I'll make this changes again.

[mattn]

golang/go#51082

gofmt is changed

[muesli]

golang/go#51082

gofmt is changed

Understood! This seems to be a pending change for 1.19, tho? Can't reproduce it with 1.18.3 for what it's worth. I think we should stick to the existing format until this gofmt change is part of a stable Go release.

[mattn]

Reverted format

[mattn]

I can squash this changes. Do you want?

[muesli]

I can squash this changes. Do you want?

Thanks, but no need to, can do that here just fine!

[meowgorithm]

Small note that this will close #393.

[meowgorithm]

Thank you so much for the contribution, @mattn. Multi-byte support is really important to us. Cheers 🍻.