Merge pull request #1617 from richardmiller/adding_yaml_note_to_di

Added a note that YAML component needed to load YAML files into service ...

Author: weaverryan

components/dependency_injection/introduction.rst

@@ -200,7 +200,7 @@ Setting Up the Container with Configuration Files
 As well as setting up the services using PHP as above you can also use configuration
 files. To do this you also need to install :doc:`the Config Component</components/config/introduction>`.
 
-Loading an xml config file:
+Loading an XML config file:
 
 .. code-block:: php
 
@@ -212,7 +212,7 @@ Loading an xml config file:
     $loader = new XmlFileLoader($container, new FileLocator(__DIR__));
     $loader->load('services.xml');
 
-Loading a yaml config file:
+Loading a YAML config file:
 
 .. code-block:: php
 
@@ -224,6 +224,11 @@ Loading a yaml config file:
     $loader = new YamlFileLoader($container, new FileLocator(__DIR__));
     $loader->load('services.yml');
 
+.. note::
+
+    If you want to load YAML config files then you will also need to install
+    :doc:`The YAML component</components/yaml>`.
+
 The ``newsletter_manager`` and ``mailer`` services can be set up using config files:
 
 .. configuration-block::