Improve and fix AP changelog, sync release notes [ci skip]

actionpack/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
-*   Add routes to page while debugging a RoutingError in development. *Richard Schneeman and Mattt Thompson*
+*   Show routes in exception page while debugging a `RoutingError` in development. *Richard Schneeman and Mattt Thompson*
 
 *   Add `ActionController::Flash.add_flash_types` method to allow people to register their own flash types. e.g.:
 
@@ -8,7 +8,7 @@
           add_flash_types :error, :warning
         end
 
-    If you add the above code, you can use `<%= error %>` in an erb, and `rediect_to /foo, :error => 'message'` in a controller.
+    If you add the above code, you can use `<%= error %>` in an erb, and `redirect_to /foo, :error => 'message'` in a controller.
 
     *kennyj*
 

guides/source/4_0_release_notes.textile

@@ -122,6 +122,16 @@ h3. Action Pack
 
 h4. Action Controller
 
+* Add <tt>ActionController::Flash.add_flash_types</tt> method to allow people to register their own flash types. e.g.:
+
+<ruby>
+class ApplicationController
+  add_flash_types :error, :warning
+end
+</ruby>
+
+If you add the above code, you can use <tt><%= error %></tt> in an erb, and <tt>redirect_to /foo, :error => 'message'</tt> in a controller.
+
 * Remove Active Model dependency from Action Pack.
 
 * Support unicode characters in routes. Route will be automatically escaped, so instead of manually escaping:
@@ -186,6 +196,8 @@ h5(#actioncontroller_deprecations). Deprecations
 
 h4. Action Dispatch
 
+* Show routes in exception page while debugging a <tt>RoutingError</tt> in development.
+
 * Include <tt>mounted_helpers</tt> (helpers for accessing mounted engines) in <tt>ActionDispatch::IntegrationTest</tt> by default.
 
 * Added <tt>ActionDispatch::SSL</tt> middleware that when included force all the requests to be under HTTPS protocol.