func (b *Builder) NewLine() *Builder {
	return b.add(nil, "\n")
}
NewLine appends a newline to the Builder.
package colorstring
import (
	"fmt"
)
type Builder struct {
	s string
}
func NewBuilder() *Builder {
	return &Builder{}
}
func (b *Builder) add(colorFunc ColorfFunc, format string, v ...interface{}) *Builder {
	if colorFunc == nil {
		b.s += fmt.Sprintf(format, v...)
	} else {
		b.s += colorFunc(format, v...)
	}
	return b
}