[ticket/11777] Rename the extension template listener subdirectory to 'event/'

Per suggestion of EXreaction and nickvergessen, do not look for extension
template event listeners in styles/[style]/template/events/ but in
styles/[style]/template/event/ (without the trailing 's') to match the way
phpBB looks for php template event listeners.

PHPBB3-11777

phpBB/phpbb/template/twig/node/event.php

@@ -19,9 +19,10 @@ if (!defined('IN_PHPBB'))
 class phpbb_template_twig_node_event extends Twig_Node
 {
 	/** 
-	 * The subdirectory in which all template event files must be placed
+	 * The subdirectory in which all template listener files must be placed
+	 * @var string
 	 */
-	const TEMPLATE_EVENTS_SUBDIRECTORY = 'events/';
+	protected $listener_directory = 'event/';
 
 	/** @var Twig_Environment */
 	protected $environment;
@@ -42,7 +43,7 @@ class phpbb_template_twig_node_event extends Twig_Node
 	{
 		$compiler->addDebugInfo($this);
 
-		$location = $this->getNode('expr')->getAttribute('name');
+		$location = $this->listener_directory . $this->getNode('expr')->getAttribute('name');
 
 		foreach ($this->environment->get_phpbb_extensions() as $ext_namespace => $ext_path)
 		{
@@ -55,19 +56,19 @@ class phpbb_template_twig_node_event extends Twig_Node
 				//  slower, but makes developing extensions easier (no need to
 				//  purge the cache when a new event template file is added)
 		        $compiler
-		            ->write("if (\$this->env->getLoader()->exists('@{$ext_namespace}/" . self::TEMPLATE_EVENTS_SUBDIRECTORY . "{$location}.html')) {\n")
+		            ->write("if (\$this->env->getLoader()->exists('@{$ext_namespace}/{$location}.html')) {\n")
 		            ->indent()
 		        ;
 			}
 
-			if (defined('DEBUG') || $this->environment->getLoader()->exists('@' . $ext_namespace . '/' . self::TEMPLATE_EVENTS_SUBDIRECTORY . $location . '.html'))
+			if (defined('DEBUG') || $this->environment->getLoader()->exists('@' . $ext_namespace . '/' . $location . '.html'))
 			{
 				$compiler
 					->write("\$previous_look_up_order = \$this->env->getNamespaceLookUpOrder();\n")
 
 					// We set the namespace lookup order to be this extension first, then the main path
 					->write("\$this->env->setNamespaceLookUpOrder(array('{$ext_namespace}', '__main__'));\n")
-					->write("\$this->env->loadTemplate('@{$ext_namespace}/" . self::TEMPLATE_EVENTS_SUBDIRECTORY . "{$location}.html')->display(\$context);\n")
+					->write("\$this->env->loadTemplate('@{$ext_namespace}/{$location}.html')->display(\$context);\n")
 					->write("\$this->env->setNamespaceLookUpOrder(\$previous_look_up_order);\n")
 				;
 			}