update dart to .23

public/docs/dart/latest/guide/displaying-data.jade

@@ -52,7 +52,7 @@
       description: Dart version of Angular 2 example, Displaying Data
       version: 0.0.1
       dependencies:
-        angular2: 2.0.0-alpha.22
+        angular2: 2.0.0-alpha.23
         browser: any
   p.
    All of this code should look familiar from the previous page,
@@ -370,7 +370,7 @@
       description: Dart version of Angular 2 example, Displaying Data
       version: 0.0.1
       dependencies:
-        angular2: 2.0.0-alpha.22
+        angular2: 2.0.0-alpha.23
         browser: any
 .l-main-section
   h2#section-explanations Explanations

public/docs/dart/latest/guide/setup.jade

@@ -30,7 +30,7 @@
     description: Dart version of Angular 2 example, Getting Started
     version: 0.0.1
     dependencies:
-      angular2: 2.0.0-alpha.22
+      angular2: 2.0.0-alpha.23
       browser: any
   p.
     Run <b>pub get</b> to download the packages your app depends on.

public/docs/dart/latest/guide/user-input.jade

@@ -199,5 +199,5 @@
       description: Dart version of Angular 2 example, Responding to User Input
       version: 0.0.1
       dependencies:
-        angular2: 2.0.0-alpha.22
+        angular2: 2.0.0-alpha.23
         browser: any

public/docs/dart/latest/quickstart.jade

@@ -30,14 +30,14 @@ p.
   p.
     In <code>pubspec.yaml</code>, add the angular2 and browser packages as dependencies.
     Angular 2 is changing rapidly, so specify an exact version:
-    <b>2.0.0-alpha.22</b>.
+    <b>2.0.0-alpha.23</b>.
 
   pre.prettyprint.linenums.lang-basic
     code.
       name: hello_world
       version: 0.0.1
       dependencies:
-        angular2: 2.0.0-alpha.22
+        angular2: 2.0.0-alpha.23
         browser: any
   p.
     In the same directory, run <code>pub get</code>