fix a doctest

Author: williamstein

src/sage/rings/polynomial/term_order.py

@@ -615,7 +615,7 @@ def macaulay2_str(self):
 
         EXAMPLE:
             sage: P = PolynomialRing(GF(127),8,names='x',order='degrevlex(3),lex(5)')
-            sage: P._macaulay2_()
+            sage: P._macaulay2_()          # optional -- requires macaulay2
             ZZ/127 [x0, x1, x2, x3, x4, x5, x6, x7, MonomialOrder => {GRevLex => 3, Lex => 5}, MonomialSize => 16]
         """
         return self.__macaulay2_str