Motivation:
Currently, the condition for making a generated Java class instantiable is "class is neither abstract nor stateless".
(An instantiable class receives a public constructor and equals/hashCode/toString/with methods.)
This is inconsistent with Pkl and codegen-kotlin, both of which support instantiation of stateless classes.
Changes:
Widen condition for making a class instantiable to "class is neither abstract nor a stateless final module class".
This is consistent with codegen-kotlin, which generates object declarations (only) for stateless final module classes.
Result:
Stateless classes are instantiable in Pkl, codegen-java, and codegen-kotlin.