Remove Unnecessary Includes in Headers (#4275)

* refactor: remove unnecessary includes in headers

* fix: formatting

* chore: changelog

* fix: scrollbar

* fix: suggestions and old appbase remains

* fix: suggestion

* fix: missing Qt forward declarations

* fix: another qt include

* fix: includes for precompiled-headers=off

* Add missing `<memory>` includes

* Add missing `#pragma once`

* Fix tests

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/widgets/dialogs/SettingsDialog.hpp

@@ -1,7 +1,6 @@
 #pragma once
 
 #include "widgets/BaseWindow.hpp"
-#include "widgets/helper/SettingsDialogTab.hpp"
 
 #include <pajlada/settings/setting.hpp>
 #include <QFrame>
@@ -19,6 +18,7 @@ namespace chatterino {
 class SettingsPage;
 class SettingsDialogTab;
 class ModerationPage;
+enum class SettingsTabId;
 
 class PageHeader : public QFrame
 {