Namespace exports not working.

Documenting the export of a namespace doesn't appear to be working.
In this case we want to specifically document an external object without documenting its internals.

Example:
```
/**
* Documentation for the thing
*/
export {default as something} from "./something.js";
```

There is a workaround explained here: https://github.com/documentationjs/documentation/issues/1238#issuecomment-797420898

Documenting a `let` works but not when exporting the object directly.

What version of documentation.js are you using?: 13.1.1
How are you running documentation.js (on the CLI, Node.js API, Grunt, other?): CLI