Types cannot contain Terms, so the Symbol representation uses
GenericTypeParameterTypes whose index refers to an array of
"substitution" Terms.
We can (ab)use the PrintOptions.AlternateTypeNames mechanism
to print those GenericTypeParamTypes as if they were Terms.
A superclass requirement implies a layout requirement. We don't
want the layout requirement to be present in the minimal
signature, so instead of adding a pair of requirements:
T.[superclass: C<X, Y>] => T
T.[layout: _NativeClass] => T
Add this pair of requirements:
T.[superclass: C<X, Y>] => T
[superclass: C<X, Y>].[layout: _NativeClass] => [superclass: C<X, Y>] [permanent]
Completion then derives the rule as a consequence:
T.[layout: _NativeClass] => T
Since this rule is a consequence of the other two rules, homotopy
reduction will mark it redundant.
Also, introduce the layout requirement implied by a superclass requirement
when lowering requirements, instead of when building the property map.
Right now this is functionally equivalent, but if we ever start to
test properties by checking for joinability of T with T.[p] instead of
looking at the property map entry of T, this new formulation is the
right one.
