<feature> Update php code doc for notifications

Author: shakaran

Event/MessageListEvent.php

@@ -35,15 +35,17 @@ class MessageListEvent extends ThemeEvent
     /**
      * MessageListEvent constructor.
      *
-     * @param null $max
+     * @param integer $max Maximun number of notifications displayed in panel
      */
     public function __construct($max = NULL)
     {
         $this->max = $max;
     }
 
     /**
-     * @return null
+     * Get the maximun number of notifications displayed in panel
+     * 
+     * @return integer
      */
     public function getMax()
     {

Event/NotificationListEvent.php

@@ -28,15 +28,17 @@ class NotificationListEvent extends ThemeEvent
     /**
      * NotificationListEvent constructor.
      *
-     * @param null $max
+     * @param integer $max Maximun number of notifications displayed in panel
      */
     public function __construct($max = NULL)
     {
         $this->max = $max;
     }
 
     /**
-     * @return null
+     * Get the maximun number of notifications displayed in panel
+     * 
+     * @return integer
      */
     public function getMax()
     {

Event/TaskListEvent.php

@@ -20,15 +20,17 @@ class TaskListEvent extends ThemeEvent
     /**
      * TaskListEvent constructor.
      *
-     * @param $max
+     * @param integer $max Maximun number of notifications displayed in panel
      */
     public function __construct($max = NULL)
     {
         $this->max = $max;
     }
 
     /**
-     * @return mixed
+     * Get the maximun number of notifications displayed in panel
+     * 
+     * @return integer
      */
     public function getMax()
     {