fixed pygments code name for json

Author: fabpot

book/part01.rst

@@ -108,7 +108,7 @@ To install the Symfony2 Components that we need for our framework, we are
 going to use `Composer`_, a project dependency manager for PHP. First, list
 your dependencies in a ``composer.json`` file:
 
-.. code-block:: json
+.. code-block:: javascript
 
     {
         "require": {

book/part02.rst

@@ -127,7 +127,7 @@ layer.
 To use this component, open the ``composer.json`` file and add it as a
 dependency for the project:
 
-.. code-block:: json
+.. code-block:: javascript
 
     {
         "require": {

book/part07.rst

@@ -85,7 +85,7 @@ To wrap up the refactoring, let's move everything but routes definition from
 For the classes defined under the ``Simplex`` and ``Calendar`` namespaces to
 be autoloaded, update the ``composer.json`` file:
 
-.. code-block:: json
+.. code-block:: javascript
 
     {
         "require": {

book/part09.rst

@@ -17,7 +17,7 @@ pattern, the *Observer*, to allow any kind of behaviors to be attached to our
 framework; the Symfony2 EventDispatcher Component implements a lightweight
 version of this pattern:
 
-.. code-block:: json
+.. code-block:: javascript
 
     {
         "require": {