docs(cookbook/graphql): remove rxjs-extensions in favor of explict imports (angular#3075)

Author: Urigo

public/docs/_examples/heroes-graphql/ts/app/app.module.ts

@@ -1,8 +1,5 @@
 // #docplaster
 // #docregion
-// #docregion rxjs-extensions
-import './rxjs-extensions';
-// #enddocregion rxjs-extensions
 
 // #docregion v1, v2
 import { NgModule }      from '@angular/core';
@@ -45,7 +42,7 @@ import { HeroSearchComponent }  from './hero-search.component';
   // #docregion search
   declarations: [
     // ...
-// #enddocregion apollo-ngmodule    
+// #enddocregion apollo-ngmodule
     AppComponent,
     DashboardComponent,
     HeroDetailComponent,

public/docs/_examples/heroes-graphql/ts/app/hero-search.component.ts

@@ -2,8 +2,20 @@
 // #docregion
 import { Component, OnInit } from '@angular/core';
 import { Router }            from '@angular/router';
+
+// #docregion rxjs-imports
+import { Observable }        from 'rxjs/Observable';
 import { Subject }           from 'rxjs/Subject';
 
+// Observable class extensions
+import 'rxjs/add/observable/of';
+
+// Observable operators
+import 'rxjs/add/operator/catch';
+import 'rxjs/add/operator/debounceTime';
+import 'rxjs/add/operator/distinctUntilChanged';
+// #enddocregion rxjs-imports
+
 import { Hero } from './hero';
 
 import { Angular2Apollo, ApolloQueryObservable } from 'apollo-angular';
@@ -48,7 +60,7 @@ export class HeroSearchComponent implements OnInit {
       `,
       variables: {
         search: this.searchTerms
-          .debounceTime(300)        // wait for 300ms pause in events
+          .debounceTime(300)        // wait 300ms after each keystroke before considering the term
           .distinctUntilChanged()   // ignore if next search term is same as previous
       },
       forceFetch: true