docs: fix flex module import in user stories

Author: RicardoVaranda

docs/documentation/stories/include-angular-flex.md

@@ -17,7 +17,7 @@ import { FlexLayoutModule } from '@angular/flex-layout';
 @NgModule({
   imports: [
     ...
-    FlexLayoutModule.forRoot()
+    FlexLayoutModule
   ],
   ...
 })
@@ -74,4 +74,4 @@ Among what you should see are - a light yellow header that is the entire width o
 
  - [Installation](https://github.com/angular/flex-layout#installation)
  - [API Overview](https://github.com/angular/flex-layout/wiki/API-Overview)
- - [Demo](https://tburleson-layouts-demos.firebaseapp.com/#/docs)
+ - [Demo](https://tburleson-layouts-demos.firebaseapp.com/#/docs)