func (ins *Jump) String() string {
	return fmt.Sprintf("jump to #%d", ins.To)
}
String is the human-readable description of the instruction.
package vm
import (
	"fmt"
)
type Jump struct {
	To int
}
func (ins *Jump) Execute(i *int, vm *VM) error {
	*i = ins.To
	return nil
}