message: docs(http): Make name of injected HttpTestingController consistent
diff: @@ -614,7 +614,7 @@ it('expects a GET request', inject([HttpClient, HttpTestingController], (http: H
  req.flush({name: 'Test Data'});
  // Finally, assert that there are no outstanding requests.
  - mockHttp.verify();
  + httpMock.verify();
  }));
  ```
  @@ -622,7 +622,7 @@ The last step, verifying that no requests remain outstanding, is common enough f
  ```javascript
  afterEach(inject([HttpTestingController], (httpMock: HttpTestingController) => {
  - mockHttp.verify();
  + httpMock.verify();
  }));
  ```
  @@ -631,7 +631,7 @@ afterEach(inject([HttpTestingController], (httpMock: HttpTestingController) => {
  If matching by URL isn't sufficient, it's possible to implement your own matching function. For example, you could look for an outgoing request that has an Authorization header:
  ```javascript
  -const req = mockHttp.expectOne((req) => req.headers.has('Authorization'));
  +const req = httpMock.expectOne((req) => req.headers.has('Authorization'));
  ```
  Just as with the `expectOne()` by URL in the test above, if 0 or 2+ requests match this expectation, it will throw.
  @@ -642,7 +642,7 @@ If you need to respond to duplicate requests in your test, use the `match()` API
  ```javascript
  // Expect that 5 pings have been made and flush them.
  -const reqs = mockHttp.match('/ping');
  +const reqs = httpMock.match('/ping');
  expect(reqs.length).toBe(5);
  reqs.forEach(req => req.flush());
  ```
  