Refactor namespaces

- Remove unused use statements
- Add required use statements
- Escape global classes

src/Content/ForumManager.php

@@ -6,7 +6,6 @@
 namespace Friendica\Content;
 
 use Friendica\Core\Protocol;
-use Friendica\Content\Feature;
 use Friendica\Content\Text\HTML;
 use Friendica\Core\L10n;
 use Friendica\Core\Renderer;

src/Content/Text/Markdown.php

@@ -9,7 +9,6 @@ namespace Friendica\Content\Text;
 use Friendica\BaseObject;
 use Friendica\Model\Contact;
 use Michelf\MarkdownExtra;
-use Friendica\Content\Text\HTML;
 
 /**
  * Friendica-specific usage of Markdown

src/Content/Widget.php

@@ -4,8 +4,6 @@
  */
 namespace Friendica\Content;
 
-use Friendica\Content\ContactSelector;
-use Friendica\Content\Feature;
 use Friendica\Core\Addon;
 use Friendica\Core\Config;
 use Friendica\Core\L10n;

src/Content/Widget/TagCloud.php

@@ -11,7 +11,6 @@ use Friendica\Core\Renderer;
 use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\Model\Item;
-use Friendica\Util\Security;
 
 /**
  * TagCloud widget