Decimal value of zero obtained from subtraction does not equal to other zero values

[mdawar]

If we subtract the same values, the result value is not reported as equal to other zero values by the Cmp and Equal methods and the direct == equality operator, this is due to the result having the field neg set to true after the subtraction.

package main

import (
	"fmt"

	"github.com/quagmt/udecimal"
)

func main() {
	zero := udecimal.MustParse("1").Sub(udecimal.MustParse("1"))

	fmt.Println(zero.IsZero())             // true
	fmt.Println(udecimal.Zero == zero)     // false
	fmt.Println(zero.Cmp(udecimal.Zero))   // -1
	fmt.Println(zero.Equal(udecimal.Zero)) // false
}