fix static

Author: engcom-Charlie

app/code/Magento/Downloadable/Block/Sales/Order/Email/Items/Downloadable.php

@@ -81,6 +81,8 @@ public function getLinks()
     }
 
     /**
+     * Returns links title
+     *
      * @return null|string
      */
     public function getLinksTitle()
@@ -92,6 +94,8 @@ public function getLinksTitle()
     }
 
     /**
+     * Returns purchased link url
+     *
      * @param Item $item
      * @return string
      */