fixed rst markup

doc/changelog.rst

@@ -3,35 +3,35 @@ Changelog
 
 This changelog references all backward incompatibilities as we introduce them:
 
-* 2011-09-22: `ExtensionInterface` has been renamed to
+* **2011-09-22**: `ExtensionInterface` has been renamed to
   `ServiceProviderInterface`. All built-in extensions have been renamed
   accordingly (for instance, `Silex\Extension\TwigExtension` has been renamed
   to `Silex\Provider\TwigServiceProvider`)
 
-* 2011-09-22: The way reusable applications work has changed. The `mount()`
+* **2011-09-22**: The way reusable applications work has changed. The `mount()`
   method now takes an instance of `ControllerCollection` instead of an
   `Application` one.
 
-    Before:
+    Before::
 
         $app = new Application();
         $app->get('/bar', function() { return 'foo'; });
 
         return $app;
 
-    After:
+    After::
 
         $app = new ControllerCollection();
         $app->get('/bar', function() { return 'foo'; });
 
         return $app;
 
-* 2011-08-08: The controller method configuration is now done on the Controller itself
+* **2011-08-08**: The controller method configuration is now done on the Controller itself
 
-    Before:
+    Before::
 
         $app->match('/', function () { echo 'foo'; }, 'GET|POST');
 
-    After:
+    After::
 
         $app->match('/', function () { echo 'foo'; })->method('GET|POST');