message: docs: Update Contribution guides with TS
diff: @@ -93,9 +93,9 @@ The best way to understand how to create new components is looking at the other
  A simple component folder is composed by three files:
  - - `Component.js` with the source code.
  + - `Component.tsx` with the source code.
  - `Component.md` with the docs.
  - - `index.js` exporting the component as default.
  + - `index.ts` exporting the component as default.
  Also, an entry should be added to [`packages/reakit/src/index.ts`](https://github.com/reakit/reakit/blob/master/packages/reakit/src/index.ts).
  