Correct Javadoc example in SqlStaticAggFunction#constant

The Javadoc in SqlStaticAggFunction#constant says:

GROUPING(deptno) expands to literal 1 if the aggregate has GROUP BY deptno

However, this "1" seems incorrect (it should rather be "0"). If we look at the actual implementation of this logic in SqlGroupingFunction#constant, or this test agg.iq, it seems in these cases the GROUPING is expanded to a constant 0.