PositiveInteger should have OrderedMonoid

[oldk1331]

I think PositiveInteger satisfy the definition of OrderedMonoid,
so I propose following change.

--- a/src/algebra/integer.spad
+++ b/src/algebra/integer.spad
@@ -259,7 +259,7 @@
 ++ Keywords: positive integer
 ++ Description: \spadtype{PositiveInteger} provides functions for
 ++   positive integers.
-PositiveInteger : Join(OrderedAbelianSemiGroup, Monoid, CommutativeStar,
+PositiveInteger : Join(OrderedAbelianSemiGroup, OrderedMonoid,
CommutativeStar,
                        ConvertibleTo InputForm) with
             gcd : (%, %) -> %
               ++ gcd(a, b) computes the greatest common divisor of two

[Waldek Hebisch]

OK, please commit

--
Waldek Hebisch