Module Augmentation!

https://blogs.msdn.microsoft.com/typescript/2016/02/22/announcing-typescript-1-8-2/

``` ts
import { Scale } from "./scale";
import "./advancedScale";
```

Start with the linked TypeScript 1.8 announcement and the module augmentation example in the issue. Determine where this topic belongs in the book, then document the shown import pattern with enough context for readers to understand what should be covered.

Written by the indexing model from the issue text.