Also updated test real002 to use the actual Control.App from
libs/base/Control/App.idr. Before it was using a different version that
existed within its test directory, tests/idris2/real002/Control/App.idr
I'm playing with some linear structures and finding these useful a lot,
so good to have a consistent syntax for it. '#' is chosen because it's
short, looks a bit like a cross if you look at it from the right angle
(!) and so as not to clash with '@@' in preorder reasoning syntax.
