SCSS variables from imported modules don't resolve

Here's a question / possible feature request for projects with node packages, such as those using Webpack and `sass-loader`.

If I have a file like this in my project dir:

```scss
// _variables.scss
$coolcolor: $f00;
```

Pigments will read it and highlight `$coolcolor` in red as expected throughout my project, even if I haven't opened the file in Atom. (This is great)

However, if I bring in some variables form a package in `node_modules`:

```scss
// _variables.scss
@import "~bulma/sass/utilities/_all";

$coolcolor: $f00;
```
The bulma import in the example above brings in variables like `$primary` and `$secondary`, but those won't be highlighted by Pigments.

Maybe this is the intended behavior, because `node_modules/*` is in the "Ignored Names" section in the Pigment options, but I have explicitly imported the file into my project, so I might expect Pigments to read that file. Is there a way to do this without just whitelisting all of `node_modules/`?