OpenSSL 3.4.1 mnemonics are not compatible with OpenSSL 3.4.0 ones since
they were renumbered [1, 2]. Consequently, `_ssl_data_34.h` is renamed to
`_ssl_data_340.h` and `_ssl_data_34.h` now contains OpenSSL 3.4.1 mnemonics.
We also refine the mnemonics that are selected, discarding those that are
mnemonic-like but should not be used as such. More precisely, we remove
the ERR_LIB_MASK and ERR_LIB_OFFSET entries from OpenSSL 1.1.1 data.
[1]: https://github.com/openssl/openssl/issues/26316
[2]: https://github.com/openssl/openssl/issues/26388
- Add `git describe` output to headers generated by `make_ssl_data.py`
This info is more important than the date when the file was generated.
It does mean that the tool now requires a Git checkout of OpenSSL,
not for example a release tarball.
- Regenerate the older file to add the info.
To the other older file, add a note about manual edits.
- Add notes on how to add a new OpenSSL version
- Add 3.4 error messages and multissl tests
