message: docs: fix the code sample displayed in the "reusable animations" guide
  Currently the code sample displayed in this guide is not a valid.
  The `trigger` is directly used in the `@Component` decorator.
  It should instead be in the `animations` array of the `@Component` decorator.
  PR Close
diff: // #docplaster
  // #docregion reusable
  import { Component } from '@angular/core';
  -import { useAnimation, transition, trigger, style, animate } from '@angular/animations';
  +import { transition, trigger, useAnimation } from '@angular/animations';
  import { transAnimation } from './animations';
  @Component({
  -// #enddocregion reusable
  selector: 'app-open-close-reusable',
  -// #docregion runtime
  animations: [
  - transition('open => closed', [
  - style({
  - height: '200 px',
  - opacity: '{{ opacity }}',
  - backgroundcolor: 'yelow'
  - }),
  - animate('{{ time }}'),
  - ], {
  - params: {
  - time: '1s',
  - opacity: '1'
  - }
  - }),
  -// #enddocregion runtime
  -// #docregion reusable
  trigger('openClose', [
  transition('open => closed', [
  useAnimation(transAnimation, {
  @@ -36,10 +19,9 @@ import { transAnimation } from './animations';
  })
  ])
  ])
  -// #enddocregion reusable
  + ],
  templateUrl: 'open-close.component.html',
  styleUrls: ['open-close.component.css']
  -// #docregion reusable
  })
  // #enddocregion reusable
  export class OpenCloseReusableComponent { }
  