docs(testing): fix broken links (#2624)

Author: mauricedb

public/docs/ts/latest/guide/testing.jade

@@ -45,7 +45,7 @@ block includes
   1. [Test a component with an external template](#component-with-external-template)
     - [_async_](#async-in-before-each) in `beforeEach`
     - [_compileComponents_](#compile-components)
-  1. [Test a component with inputs and outputs](#component-with-inputs-output)
+  1. [Test a component with inputs and outputs](#component-with-inputs-outputs)
     - [_triggerEventHandler_](#trigger-event-handler)
   1. [Test a component inside a test host component](#component-inside-test-host)
   <br><br>
@@ -74,7 +74,7 @@ block includes
   1. [Angular testing utility APIs](#atu-apis)
     - [Stand-alone functions](#atu-apis): `async`, `fakeAsync`, etc.
     - [_TestBed_](#testbed-class-summary)
-    - [_ComponentFixture_](#component-fixture-class-summary)
+    - [_ComponentFixture_](#component-fixture-api-summary)
     - [_DebugElement_](#debug-element-details)
   1. [FAQ](#faq "Frequently asked questions")
 :marked
@@ -582,7 +582,7 @@ a(href="#top").to-top Back to top
   the configuration adds a `UserService` provider to the `providers` list.
   But not the real `UserService`.
 
-#get-injected-service 
+#service-test-doubles 
 :marked
   ## Provide service test doubles