docs: adjust page heading levels (#2813)

* docs: adjust page heading levels

Only the page TOC should be at heading level 1. All other headings
should start at level 2. This commit also removes duplicate headings,
in continuation of #2796.

(This fix is necessary to support an auto-TOC feature.)

Author: chalin

public/docs/ts/_cache/glossary.jade

@@ -9,8 +9,6 @@ block includes
 - var _decoratorLink = '<a href="#' + _decorator + '">' + _decorator + '</a>'
 
 :marked
-  # Angular 2 Glossary
-
   Angular 2 has a vocabulary of its own.
   Most Angular 2 terms are everyday English words
   with a specific meaning within the Angular system.

public/docs/ts/_cache/guide/lifecycle-hooks.jade

@@ -3,9 +3,13 @@ block includes
 
 - var top="vertical-align:top"
 
+figure
+  img(src="/resources/images/devguide/lifecycle-hooks/hooks-in-sequence.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:30px")
+
 :marked
-  # Component Lifecycle
-  A Component has a lifecycle managed by Angular itself. Angular creates it, renders it, creates and renders its children,
+  A component has a lifecycle managed by Angular itself.
+  
+  Angular creates it, renders it, creates and renders its children,
   checks it when its data-bound properties change, and destroys it before removing it from the DOM.
 
   Angular offers **component lifecycle hooks**

public/docs/ts/_cache/guide/server-communication.jade

@@ -38,7 +38,7 @@ block includes
 
 .l-main-section
 :marked
-  # Demos
+  ## Demos
 
   This chapter describes server communication with the help of the following demos
 
@@ -139,7 +139,7 @@ figure.image-display
 a#oninit
 a#HeroListComponent
 :marked
-  ## The *HeroListComponent* class
+  ### The *HeroListComponent* class
   Here's the component class:
 +makeExample('server-communication/ts/app/toh/hero-list.component.ts','component', 'app/toh/hero-list.component.ts (class)')  
 :marked
@@ -219,7 +219,7 @@ a#HeroService
 
   .l-main-section
   :marked
-    # RxJS Library
+    ## RxJS Library
     [RxJS](https://github.com/ReactiveX/RxJS) ("Reactive Extensions") is a 3rd party library, endorsed by Angular,
     that implements the [*asynchronous observable*](https://www.youtube.com/watch?v=UHI0AzD_WfY "Rob Wormald on observables") pattern.
 

public/docs/ts/latest/cookbook/index.jade

@@ -1,8 +1,6 @@
 include ../_util-fns 
 
 :marked
-  # Angular Cookbook
-  
   The *Cookbook* offers answers to common implementation questions.
 
   Each cookbook chapter is a collection of recipes focused on a particular Angular feature or application challenge

public/docs/ts/latest/cookbook/ngmodule-faq.jade

@@ -2,8 +2,6 @@ block includes
   include ../_util-fns
 
 :marked
-  # FAQs
-
   **Angular Modules** help organize an application into cohesive blocks of functionality.
 
   The [Angular Modules chapter](../guide/ngmodule.html) covers the concepts and takes you step by step

public/docs/ts/latest/glossary.jade

@@ -9,8 +9,6 @@ block includes
 - var _decoratorLink = '<a href="#' + _decorator + '">' + _decorator + '</a>'
 
 :marked
-  # Angular Glossary
-
   Angular has a vocabulary of its own.
   Most Angular terms are everyday English words
   with a specific meaning within the Angular system.

public/docs/ts/latest/guide/browser-support.jade

@@ -3,7 +3,6 @@ block includes
   - var _at_angular = '@angular'
 
 :marked
-  # Browser support #  
   Angular supports most recent browsers. This includes the following specific versions:
 
 table
@@ -61,7 +60,7 @@ table
     <a href="https://www.browserstack.com" target="_blank">Browserstack</a>.
 
 :marked
-  # Polyfills #
+  ## Polyfills #
   Angular is built on the latest standards of the web platform.
   Targeting such a wide range of browsers is challenging because they do not support all features of modern browsers.
 
@@ -81,7 +80,7 @@ table
     Note that polyfills cannot magically transform an old, slow browser into a modern, fast one.
 
 :marked
-  ## Mandatory polyfills ##
+  ### Mandatory polyfills ##
   These are the polyfills required to run an Angular application on each supported browser:
 
 table
@@ -103,7 +102,7 @@ table
         [ES6<br>classList](#classlist)
 
 :marked
-  ## Optional browser features to polyfill ##
+  ### Optional browser features to polyfill ##
   Some features of Angular may require additional polyfills.
 
   For example, the animations library relies on the standard web animation API, which is only available in Chrome and Firefox today.
@@ -156,7 +155,7 @@ table
     td IE 9
 
 :marked
-  ## Suggested polyfills ##
+  ### Suggested polyfills ##
   Below are the polyfills which are used to test the framework itself. They are a good starting point for an application. 
 
 table

public/docs/ts/latest/guide/change-log.jade

@@ -2,8 +2,6 @@ block includes
   include ../_util-fns
 
 :marked
-  # Documentation Change Log
-
   The Angular documentation is a living document with continuous improvements.
   This log calls attention to recent significant changes.
 

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

@@ -10,7 +10,7 @@ figure
   <br style="clear:left;">
 
 :marked
-  # Organization
+  ## Organization
 
   The documentation is divided into major thematic sections, each
   a collection of pages devoted to that theme.
@@ -53,7 +53,7 @@ table(width="100%")
       :marked
         Recipes for specific application challenges, mostly code snippets with a minimum of exposition.
 :marked
-  # Learning path
+  ## Learning path
   You don't have to read the guide straight through.  Most pages stand on their own.
 
   For those new to Angular, the recommended learning path runs through the *Guide* section:
@@ -81,7 +81,7 @@ table(width="100%")
   After reading the above sections, you can skip to any other pages on this site.
 
 :marked
-  # Code samples
+  ## Code samples
 
   Each page includes code snippets that you can reuse in your applications.
   These snippets are excerpts from a sample application that accompanies the page.
@@ -98,15 +98,15 @@ block example-links
   The rest of the pages highlight key points in code rather than explain each step necessary to build the sample.
   You can always get the full source through the #{_liveLink}.
 
-  # Reference pages
+  ## Reference pages
 
   The [Cheat Sheet](cheatsheet.html) lists Angular syntax for common scenarios.
 
   The [Glossary](glossary.html) defines terms that Angular developers should know.
 
   The [API Reference](../api/) is the authority on every public-facing member of the Angular libraries.
 
-  # Feedback
+  ## Feedback
 
   We welcome feedback! 
 

public/docs/ts/latest/guide/lifecycle-hooks.jade

@@ -3,10 +3,9 @@ block includes
 
 - var top="vertical-align:top"
 
-:marked
-  # Component Lifecycle
 figure
-  img(src="/resources/images/devguide/lifecycle-hooks/hooks-in-sequence.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:30px" )
+  img(src="/resources/images/devguide/lifecycle-hooks/hooks-in-sequence.png" alt="Us" align="left" style="width:200px; margin-left:-40px;margin-right:30px")
+
 :marked
   A component has a lifecycle managed by Angular itself.