inherit parent docstring in case no docstring was provided in child member

[yoav-steinberg]

/// Some docs
class Parent {
   // Some docs
   method() {};
}

class Child extendes Parent { // Inherited class with no docs should use the docs from `Parent`?
  method() {}; // Overridden method with no docs should use the docs from `Parent.method`
}

This should also be true for interface implementations and struct field overriding.