Fix documentation for function objects with map/reduce

The documentation claims that function objects just work with
map-reduce. They work for the map function, but not for the reduce
function. Making them work for the reduce function was deemed
too complex for questionable benefit, so this patch explains
the situation and provides a work-around.

Task-number: QTBUG-22710
Change-Id: I7f706468e36031bc261234310d331001b96e5137
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>
Reviewed-by: Nico Vertriest <nico.vertriest@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

0 files changed, 0 insertions, 0 deletions