refactor: html format (#3062)

* refactor: html format

Fix a few small bugs too

* fix

* fix

* trigger build

* striptags instead of encode title

lib/FormatInterface.php

@@ -42,7 +42,7 @@ interface FormatInterface
      * Return items
      *
      * @throws \LogicException if the items are not set
-     * @return array The items
+     * @return FeedItem[] The items
      */
     public function getItems();