Completions inside JSDoc

**TypeScript Version:**  nightly (2.4.0-dev.20170515)

**Code**

```ts
///<reference path="fourslash.ts" />

/////**
//// * @param fo/**/
//// */
////function f(foo: number) {}

goTo.marker();
debug.printCompletionListMembers();
```

**Expected behavior:**

Shows completions from the function's parameters.

**Actual behavior:**

No useful completions.