style(docs-infra): fix docs examples for tslint rule import-spacing (#38143)

This commit updates the docs examples to be compatible with the
`import-spacing` tslint rule.

This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.

PR Close #38143

aio/content/examples/pipes/src/app/fetch-json.pipe.ts

@@ -1,5 +1,5 @@
 // #docregion
-import { HttpClient }          from '@angular/common/http';
+import { HttpClient } from '@angular/common/http';
 import { Pipe, PipeTransform } from '@angular/core';
 
 // #docregion pipe-metadata

aio/content/examples/pipes/src/app/flying-heroes.component.ts

@@ -1,8 +1,8 @@
 // #docplaster
 // #docregion
-import { Component }              from '@angular/core';
+import { Component } from '@angular/core';
 
-import { HEROES }                 from './heroes';
+import { HEROES } from './heroes';
 
 @Component({
   selector: 'app-flying-heroes',