Update rotating_file_sink-inl.h

include/spdlog/sinks/rotating_file_sink-inl.h

@@ -50,7 +50,7 @@ SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename
 
     filename_t basename, ext;
     std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-    return fmt::format(SPDLOG_FMT_RUNTIME(SPDLOG_FILENAME_T("{}.{}{}")), basename, index, ext);
+    return fmt::format(SPDLOG_FILENAME_T(SPDLOG_FMT_RUNTIME("{}.{}{}")), basename, index, ext);
 }
 
 template<typename Mutex>