[api-documenter] Annotations on type alias parameters are ignored

[razzp]

Summary

Annotating a type alias as a whole works fine, but individual paramaters are ignored.

Repro steps

Consider the following:

/**
 * This is a type alias.
 *
 * @public
 */
type Foo = {
    /**
     * This is a parameter.
     */
    bar?: unknown;
};

Expected result

For the parameter bar to have its description displayed in the generated markdown file.

Actual result

Generated markdown file:

---

Foo type

This is a type alias.

Signature:

type Foo = {
    bar?: unknown;
};

---

Standard questions

Please answer these questions to help us investigate your issue more quickly:

Question	Answer
@microsoft/api-documenter version?	7.27.4
Operating system?	Windows
Documentation target?	Markdown
Would you consider contributing a PR?	Yes
TypeScript compiler version?	5.8.2
Node.js version (node -v)?	24.11.0