message: chore(docs): updated rollup guide
diff: @@ -15,7 +15,8 @@ npm install ng2-bootstrap bootstrap --save
  Open the module file where you want to include ng2-bootstrap (most probably `app.module.ts`) and import either specific ng2-bootstrap modules by listing them in the import statement and then in the import array of the Angular 2 module
  ```typescript
  -import { AlertModule, ModalModule } from 'ng2-bootstrap';
  +import { AlertModule } from 'ng2-bootstrap/alert';
  +import { ModalModule } from 'ng2-bootstrap/modal';
  ...
  @NgModule({
  @@ -25,7 +26,7 @@ import { AlertModule, ModalModule } from 'ng2-bootstrap';
  })
  ```
  - or use Ng2BootstrapModule (**NOT RECOMMENDED**) to import all of the modules at once:
  + **NOT RECOMMENDED**: or use Ng2BootstrapModule to import all of the modules at once:
  ```typescript
  import { Ng2BootstrapModule } from 'ng2-bootstrap';
  