Function default_exception_handler

extlibs/sol3/include/sol/sol.hpp:7426–7434

must push at least 1 object on the stack

		// must push at least 1 object on the stack
		inline int default_exception_handler(lua_State* L, optional<const std::exception&>, string_view what) {
#if defined(SOL_PRINT_ERRORS) && SOL_PRINT_ERRORS
			std::cerr << "[sol3] An exception occurred: ";
			std::cerr.write(what.data(), what.size());
			std::cerr << std::endl;
#endif
			lua_pushlstring(L, what.data(), what.size());
			return 1;
		}

		inline int call_exception_handler(lua_State* L, optional<const std::exception&> maybe_ex, string_view what) {
			lua_getglobal(L, default_exception_handler_name());