tiny fix to save/restore pos type

Author: hrissan

runtime-light/stdlib/rpc/rpc-tl-builtins.h

@@ -28,13 +28,13 @@ inline void register_tl_storers_table_and_fetcher(const array<tl_storer_ptr>& ge
   rpc_mutable_image_state.tl_fetch_wrapper = gen$t_ReqResult_fetch;
 }
 
-inline int tl_parse_save_pos() noexcept {
+inline size_t tl_parse_save_pos() noexcept {
   return RpcServerInstanceState::get().tl_fetcher.pos();
 }
 
-inline bool tl_parse_restore_pos(int pos) noexcept {
+inline bool tl_parse_restore_pos(size_t pos) noexcept {
   auto& tl_fetcher{RpcServerInstanceState::get().tl_fetcher};
-  if (pos < 0 || pos > tl_fetcher.pos()) [[unlikely]] {
+  if (pos > tl_fetcher.pos()) [[unlikely]] {
     return false;
   }
   tl_fetcher.reset(pos);