Error when dealing with multiple exports

I get this error on 5.3.3:

```
Error: Parsing file C:\Users\CMCDragonkai\Projects\js-virtualfs\lib\index.js: 'import' and 'export' may appear only with 'sourceType: module' (3:0)
at Deps.parseDeps (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\index.js:467:28)
at fromSource (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\index.js:402:44)
at C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\index.js:396:17
at ConcatStream. (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\node_modules\concat-stream\index.js:36:4
3)
at emitNone (events.js:91:20)
at ConcatStream.emit (events.js:185:7)
at finishMaybe (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\node_modules\concat-stream\node_modules\readable-stre
am\lib\_stream_writable.js:475:14)
at endWritable (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\node_modules\concat-stream\node_modules\readable-stre
am\lib\_stream_writable.js:485:3)
at ConcatStream.Writable.end (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\module-deps-sortable\node_modules\concat-stream\node_modules
\readable-stream\lib\_stream_writable.js:455:41)
at DuplexWrapper.onend (C:\Users\CMCDragonkai\Projects\js-virtualfs\node_modules\readable-stream\lib\_stream_readable.js:570:10)
```

When running `documentation build ./lib/** -f html -o ./doc` on a `lib/index.js`:

```
//@flow
export { default } from './VirtualFSSingle.js';
export { default as VirtualFS } from './VirtualFS.js';
export { default as Stat } from './Stat.js';
export { default as constants } from './constants.js';
export { default as nullDev } from './Devices/null.js';
export { default as zeroDev } from './Devices/zero.js';
export { default as fullDev } from './Devices/full.js';
export { default as randomDev } from './Devices/random.js';
export * from './VirtualFSError.js';
export * from './Devices.js';
export * from './INodes.js';
export * from './FileDescriptors.js';
export * from './Streams.js';
export * from './permissions.js';

// polyfills to be exported
// $FlowFixMe: Buffer exists
export { Buffer } from 'buffer';
export { nextTick } from 'process';
```

Full project https://github.com/MatrixAI/js-virtualfs

Reproduziere `documentation build ./lib/** -f html -o ./doc` gegen die gemeldete `lib/index.js` und verfolge dann den Parsing-Fehler durch den im Bericht gezeigten `module-deps-sortable`-Stack. Erledigt ist die Aufgabe, wenn der Build die mehreren Export-Anweisungen der Datei ohne den Fehler `sourceType: module` akzeptiert.

Vom Indexierungsmodell aus dem Issue-Text verfasst.