autocomplete doesn't work with `export { foo } from './some-file'`

Commands doesn't work with `export { } from './some_file';`. See example below.
```js
// test.js
export function foo(): string {
return 'foo';
}
export function bar(): string {
return 'bar';
}
```
**flow autocomplete**
```js
/* autocomplete_test.js */
export { } from './test.js';
// ------^ flow autocomplete not working here (returns nothing)
import { } from './test.js';
// ------^ flow autocomplete working here (returns [foo & bar])
```
**flow type-at-pos**
```js
/* type-at-pos_test.js */
export { foo } from './test.js';
// -------^ flow type-at-pos not working here (returns [(unknown)])
import { foo } from './test.js';
// -------^ flow type-at-pos working here (returns [() => string])
```
**flow get-def**
```js
/* get-def_test.js */
export { foo } from './test.js';
// -------^ flow get-def not working here (returns [test.js:0:1,0:0])
import { foo } from './test.js';
// -------^ flow get-def working here (returns [test.js:2:17,2:19])
```