e05412669c inadvertently changed the logic on Windows and made it so that supportsAnsiEscapeCodes was never checked. This fixes that regression while keeping the logic intact for other platforms.
Also get rid of the TTY wrapper struct, which was exlusively used as a
namespace - this is done by the tty.zig root struct now.
detectTTYConfig has been renamed to just detectConfig, which is enough
given the new namespace. Additionally, a doc comment had been added.