Header cleanup.

src/String/StringView.hpp

@@ -1,12 +1,11 @@
 #ifndef ARBUTILS_STRINGVIEW_HPP
 #define ARBUTILS_STRINGVIEW_HPP
 
-#include <atomic>
 #include <cstddef>
 #include <cstdint>
 #include <cstring>
 #include <memory>
-#include <string>
+#include <string_view>
 #include "BasicStringView.hpp"
 
 #if WINDOWS