iwyu: just a few changes

test/entt/core/algorithm.cpp

@@ -1,5 +1,4 @@
 #include <array>
-#include <cstdint>
 #include <vector>
 #include <gtest/gtest.h>
 #include <entt/core/algorithm.hpp>

test/entt/core/any.cpp

@@ -1,9 +1,9 @@
 #include <algorithm>
 #include <array>
+#include <cstddef>
 #include <cstdint>
 #include <cstring>
 #include <memory>
-#include <type_traits>
 #include <unordered_map>
 #include <utility>
 #include <vector>

test/lib/dispatcher/plugin/main.cpp

@@ -3,7 +3,6 @@
 #include <gtest/gtest.h>
 #include <cr.h>
 #include <entt/signal/dispatcher.hpp>
-#include <entt/signal/sigh.hpp>
 #include "../common/types.h"
 
 struct listener {

test/lib/dispatcher/shared/main.cpp

@@ -2,7 +2,6 @@
 #include <entt/core/attribute.h>
 #include <entt/core/utility.hpp>
 #include <entt/signal/dispatcher.hpp>
-#include <entt/signal/sigh.hpp>
 #include "../common/types.h"
 
 ENTT_API void trigger(entt::dispatcher &);