refactor: header cleanup

Replace a couple of header includes with forward declarations.

src/bar.cpp

@@ -7,6 +7,7 @@
 #include "bar.hpp"
 #include "client.hpp"
 #include "factory.hpp"
+#include "wlr-layer-shell-unstable-v1-client-protocol.h"
 
 namespace waybar {
 static constexpr const char* MIN_HEIGHT_MSG =

src/client.cpp

@@ -6,6 +6,9 @@
 #include "util/clara.hpp"
 #include "util/json.hpp"
 
+#include "idle-inhibit-unstable-v1-client-protocol.h"
+#include "wlr-layer-shell-unstable-v1-client-protocol.h"
+
 waybar::Client *waybar::Client::inst() {
   static auto c = new Client();
   return c;

src/modules/idle_inhibitor.cpp

@@ -1,4 +1,6 @@
 #include "modules/idle_inhibitor.hpp"
+
+#include "idle-inhibit-unstable-v1-client-protocol.h"
 #include "util/command.hpp"
 
 waybar::modules::IdleInhibitor::IdleInhibitor(const std::string& id, const Bar& bar,