use valid XML in code block

Author: xabbuh

book/service_container.rst

@@ -269,7 +269,18 @@ parameter and uses it in the service definition.
 
     .. code-block:: xml
 
-        <argument type="string">http://symfony.com/?foo=%%s&bar=%%d</argument>
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+            <services>
+                <service id="app.foo" class="AppBundle\Foo">
+                    <argument type="string"><![CDATA[http://symfony.com/?foo=%%s&bar=%%d]]></argument>
+                </service>
+            </services>
+        </container>
 
 .. caution::
 

components/dependency_injection/parameters.rst

@@ -155,7 +155,18 @@ the parameter value in one place if needed.
 
         .. code-block:: xml
 
-            <argument>http://symfony.com/?foo=%%s&bar=%%d</argument>
+            <?xml version="1.0" encoding="UTF-8" ?>
+            <container xmlns="http://symfony.com/schema/dic/services"
+                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                xsi:schemaLocation="http://symfony.com/schema/dic/services
+                    http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+                <services>
+                    <service id="app.foo" class="AppBundle\Foo">
+                        <argument type="string"><![CDATA[http://symfony.com/?foo=%%s&bar=%%d]]></argument>
+                    </service>
+                </services>
+            </container>
 
         .. code-block:: php
 

components/intl.rst

@@ -126,8 +126,10 @@ code::
 
     .. code-block:: json
 
-        "require: {
-            "symfony/icu": "1.1.*"
+        {
+            "require": {
+                "symfony/icu": "1.1.*"
+            }
         }
 
     Set the version to