fix: Build failing on Linux

lib/libimhex/include/hex.hpp

@@ -1,8 +1,5 @@
 #pragma once
 
-#include <cstdint>
-#include <cstddef>
-
 #include <hex/helpers/types.hpp>
 #include <hex/helpers/intrinsics.hpp>
 

lib/libimhex/include/hex/helpers/types.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstddef>
 #include <cstdint>
 
 using u8   = std::uint8_t;