Issue #10813: Small improvement to decimal money format recipe.

Doc/library/decimal.rst

@@ -1657,7 +1657,8 @@ to work with the :class:`Decimal` class::
            build(trailneg)
        for i in range(places):
            build(next() if digits else '0')
-       build(dp)
+       if places:
+           build(dp)
        if not digits:
            build('0')
        i = 0