simple module example generates a lint error

`index.js`:

```
'use strict';

/**
* Square a number.
* @param {number} x - base
* @returns {number} x²
*/
module.exports.square = function (x) { return x * x; };
```

`documentation --lint` output:

```
3:1 warning @memberof reference to index not found
```

I tried using an explicit `@module`:

```
'use strict';

/**
* @module test
*/

/**
* Square a number.
* @param {number} x - base
* @returns {number} x²
*/
module.exports.square = function (x) { return x * x; };
```

`documentation --lint` output:

```
3:1 warning @memberof reference to test not found
7:1 warning @memberof reference to test not found
```