redundant move in return statement [-Wredundant-move]

[CoinFuMasterShifu]

Please remove the std::move(...) in here. gcc 14.2 warns about it:

   19 |     return std::move(_errors[0].what());
      |            ~~~~~~~~~^~~~~~~~~~~~~~~~~~~
../include/rfl/generic/../parsing/to_single_error_message.hpp:19:21: note: remove 'std::move' call
In file included from ../include/sqlgen/../sqlgen/Iterator.hpp:13,
                 from ../include/sqlgen/../sqlgen.hpp:6: