In an overloaded method, the overload with the function body is the
actual method doc, and this doc is not included in the list of "additional"
overloads.
Moreover, the logic (all in dgeni-packages) is that if none of the items
has a body then we use the first overload as the actual method doc.
In the case of abstract methods, none of the methods have a body. So we
have a situation where the overloads collection does not contain the first
abstract method, even though it is not the "implementation" of the method.
Therefore we need to still render it.
Closes#25610
PR Close#25670
b1902db0cb