Rename this to renderer to be able to use it in Php Templating

src/Symfony/Bundle/TwigBundle/Resources/views/widgets.html.twig

@@ -1,6 +1,6 @@
 {% block rows %}
 {% spaceless %}
-    {{ this.errors }}
+    {{ renderer.errors }}
     {% for field in fields %}
         {{ field.row }}
     {% endfor %}

src/Symfony/Component/Form/Renderer/Plugin/FieldPlugin.php

@@ -40,7 +40,7 @@ class FieldPlugin implements RendererPluginInterface
             $name = $fieldKey;
         }
 
-        $renderer->setVar('this', $renderer);
+        $renderer->setVar('renderer', $renderer);
         $renderer->setVar('id', $id);
         $renderer->setVar('name', $name);
         $renderer->setVar('errors', $field->getErrors());