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/switcher/SwitchSplitItem.cpp

@@ -3,7 +3,9 @@
 #include "Application.hpp"
 #include "singletons/Fonts.hpp"
 #include "singletons/Theme.hpp"
+#include "singletons/WindowManager.hpp"
 #include "widgets/helper/NotebookTab.hpp"
+#include "widgets/splits/Split.hpp"
 
 namespace chatterino {
 

src/widgets/dialogs/switcher/SwitchSplitItem.hpp

@@ -1,14 +1,16 @@
 #pragma once
 
-#include "singletons/WindowManager.hpp"
 #include "widgets/dialogs/switcher/AbstractSwitcherItem.hpp"
-#include "widgets/helper/NotebookTab.hpp"
-#include "widgets/Notebook.hpp"
-#include "widgets/splits/Split.hpp"
-#include "widgets/Window.hpp"
+
+#include <QPainter>
+#include <QRect>
+#include <QSize>
 
 namespace chatterino {
 
+class SplitContainer;
+class Split;
+
 class SwitchSplitItem : public AbstractSwitcherItem
 {
 public: