Add default_path option reference

Author: yceruto

reference/configuration/twig.rst

@@ -67,6 +67,9 @@ TwigBundle Configuration ("twig")
                 decimal_point: ','
                 thousands_separator: '.'
 
+            # The following was added in Symfony 3.4.
+            default_path: '%kernel.project_dir%/templates'
+
     .. code-block:: xml
 
         <!-- app/config/config.xml -->
@@ -87,6 +90,7 @@ TwigBundle Configuration ("twig")
                 debug="%kernel.debug%"
                 strict-variables="false"
                 optimizations="true"
+                default-path="%kernel.project_dir%/templates"
             >
                 <twig:form-theme>form_div_layout.html.twig</twig:form-theme> <!-- Default -->
                 <twig:form-theme>form.html.twig</twig:form-theme>
@@ -136,6 +140,7 @@ TwigBundle Configuration ("twig")
                 'decimal_point' => ',',
                 'thousands_separator' => '.',
             ),
+            'default_path' => '%kernel.project_dir%/templates',
         ));
 
 .. caution::
@@ -338,6 +343,13 @@ on. Set it to ``0`` to disable all the optimizations. You can even enable or
 disable these optimizations selectively, as explained in the Twig documentation
 about `the optimizer extension`_.
 
+default_path
+~~~~~~~~~~~~
+
+**type**: ``string`` **default**: ``'%kernel.project_dir%/templates'``
+
+The default directory where Symfony will look for Twig templates.
+
 .. _config-twig-paths:
 
 paths
@@ -346,9 +358,13 @@ paths
 **type**: ``array`` **default**: ``null``
 
 This option defines the directories where Symfony will look for Twig templates
-in addition to the default locations (``app/Resources/views/`` and the bundles'
-``Resources/views/`` directories). This is useful to integrate the templates
-included in some library or package used by your application.
+in addition to the default locations. Symfony looks for the templates in the
+following order:
+
+1. The directories defined in this option;
+2. The ``src/Resources/views/`` directory of the application;
+3. The directory defined in the ``default_path`` option;
+4. The ``Resources/views/`` directories of the bundles used in the application.
 
 The values of the ``paths`` option are defined as ``key: value`` pairs where the
 ``value`` part can be ``null``. For example: