docs(validation): Change to 'Table of Contents'

Same change to NgModules
closes #2315

Author: DeborahK

public/docs/ts/latest/cookbook/form-validation.jade

@@ -12,7 +12,7 @@ a#top
 
 a#toc
 :marked
-  ## Contents
+  ## Table of Contents
 
     [Simple Template-Driven Forms](#template1)
 

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

@@ -17,7 +17,7 @@ block includes
   This page explains how to **create** `NgModule` classes and how to load them, 
   either immediately when the application launches or later, as needed, via the [Router](router.html).  
 
-  ## Contents
+  ## Table of Contents
   * [Angular modularity](#angular-modularity "Add structure to the app with NgModule")
   * [The application root module](#root-module "The startup module that every app requires")
   * [Bootstrap](#bootstrap "Launch the app in a browser with the root module as the entry point") the root module