Augmenting value set via template parmaeter just silently does nothing

While fixing this issue https://github.com/microsoft/typespec/pull/7421 found that this doesn't work, no error and nothing applied

```tsp
model Test {
a: T;
}

model Foo {}
model Bar is Test;

@@doc(Bar.a::type, "Some string doc");
```

[Playground Link](https://typespec.io/playground/?c=bW9kZWwgVGVzdDxUPiB7CiAgYTogVDsKfQoKxhtGb28ge33HDUJhciBpc8YvRm9vPjsKCkBAZG9jKEJhci5hOjp0eXBlLCAiU29tZSBzdHJpbmcgZG9jIik7Cg%3D%3D&e=%40typespec%2Fopenapi3&options=%7B%7D&version=1.0.x)

I think right now it is by the current name resolver design that we cannot go further but this should error at least.