FR: Warn when name starts with prop_ but is not a Property

[danr]

Being accustomed to Arbitrary instances I thought a function with type signature like

prop_test :: List Int -> Property

would trigger from jackMain, but the continue statement with comment not an object, so not a property test is triggered. It would be nice if this was logged as a warning and not just silently ignoring this prop_.

Expected output:

Warning: prop_test starts with prop_ but is not of type Property

Actual output: (nothing)

[jacobstanley]

Yeah that's a good idea!