bootdev doesn't build on Unix platforms outside of macOS and Linux

[pascalecu]

Hi! I've done go install github.com/bootdotdev/bootdev@latest on FreeBSD, however I noticed it said:

package github.com/bootdotdev/bootdev: build constraints exclude all Go files in $HOME/go/pkg/mod/github.com/bootdotdev/bootdev@v1.20.1

then I saw you have this in the main.go:

//go:build darwin || linux

Strange decision to only build on those platforms. Shouldn't it be

//go:build !windows

instead? Windows is the only non-Unix(-like) platform supported by Go, so using !windows is clearer.