help format default posix in windows, I don't want to use -tags=forceposix, let them use -tags=forcewindows about go-flags

[mind-owner]

most people use posix format, not windows, even if in windows

[johnnybubonic]

This would also be in line with Powershell's applets' preference for (almost) POSIX flags (e.g. -OutPut-Format). As such, -tags=forcedos may be more an apt tag name.

This ideally would also allow non-Windows build targets to use CMD shell argument syntax, as well. While extremely rare, this would help with documentation purposes downstream.

Implementing this would be a breaking change, however, so while recommended it should be reserved for the next major release.