warning: definition of implicit copy constructor for xxxx is deprecated because it has a user-declared copy assignment operator

would be nice to fix this warn

```
In file included from D:\git\boost_\libs\iostreams\include\boost/iostreams/stream.hpp:21:
In file included from D:\git\boost_\libs\iostreams\include\boost/iostreams/stream_buffer.hpp:21:
In file included from D:\git\boost_\libs\iostreams\include\boost/iostreams/detail/streambuf/direct_streambuf.hpp:24:
D:\git\boost_\libs\iostreams\include\boost/iostreams/detail/functional.hpp(136,45): warning: definition of implicit copy constructor for 'reset_operation>>' is deprecated because it has a user-declared copy assignment operator [-Wdeprecated-copy]
136 | BOOST_DELETED_FUNCTION(reset_operation& operator=(const reset_operation&))
| ^
D:\git\boost_\libs\preprocessor\include\boost/preprocessor/iteration/detail/limits/local_256.hpp(22,9): note: in implicit copy constructor for 'boost::iostreams::detail::reset_operation>>' first required here
22 | BOOST_PP_LOCAL_MACRO(3)
| ^
D:\git\boost_\libs\iostreams\include\boost/iostreams/detail/execute.hpp(98,20): note: expanded from macro 'BOOST_PP_LOCAL_MACRO'
98 | BOOST_PP_ENUM_PARAMS(BOOST_PP_DEC(n), c) \
| ^
D:\git\boost_\libs\preprocessor\include\boost\preprocessor\repetition\enum_params.hpp(24,71): note: expanded from macro 'BOOST_PP_ENUM_PARAMS'
24 | # define BOOST_PP_ENUM_PARAMS(count, param) BOOST_PP_REPEAT(count, BOOST_PP_ENUM_PARAMS_M, param)
| ^
D:\git\boost_\libs\iostreams\include\boost/iostreams/detail/streambuf/indirect_streambuf.hpp(202,13): note: in instantiation of function template specialization 'boost::iostreams::detail::execute_all>, boost::iostreams::detail::member_close_operation>, boost::iostreams::detail::reset_operation>>,
boost::iostreams::detail::clear_flags_operation>' requested here
202 | detail::execute_all(
| ^
D:\T60\git\boost_\libs\iostreams\include\boost/iostreams/stream_buffer.hpp(91,23): note: in instantiation of member function 'boost::iostreams::detail::indirect_streambuf, std::allocator, boost::iostreams::output_seekable>::close' requested here
91 | this->close();
| ^
D:\git\boost_\libs\utility\include\boost/utility/base_from_member.hpp(125,7): note: in instantiation of member function 'boost::iostreams::stream_buffer, std::allocator>::~stream_buffer' requested here
125 | class base_from_member
| ^
```

Start with boost/iostreams/detail/functional.hpp at line 136 and reproduce the reported deprecated-copy warning through the stream and stream_buffer include path. Trace the reset_operation instantiation shown in the diagnostic; done means the reported warning no longer appears in that build path.

Written by the indexing model from the issue text.