Missing export of `OpenSSL.SSL.FILETYPE_ASN1`

[ChristianStadelmann]

There is a mismatch between documentation of OpenSSL.SSL and the real behavior.

Steps to reproduce:

1. install pyopenssl
2. open a python shell
3. In the shell, execute: import OpenSSL
4. In the shell, execute: print(OpenSSL.SSL.FILETYPE_PEM)
5. In the shell, execute: print(OpenSSL.SSL.FILETYPE_ASN1)

What happens:

import OpenSSL
>>> print(OpenSSL.SSL.FILETYPE_PEM)
1
>>> print(OpenSSL.SSL.FILETYPE_ASN1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'OpenSSL.SSL' has no attribute 'FILETYPE_ASN1'

What should happen:

no error. The documentation claims that FILETYPE_ASN1 should be available, so it should work.

Additional info:

The code behavior is expected, see the imports of SSL.py from OpenSSL.crypto, this looks like a mismatch between documentation and code to me. Reading the value from OpenSSL.crypto.FILETYPE_ASN1 works fine (workaround).

Installed version: pyopenssl-23.1.1

[reaperhulk]

We'd be happy to take a PR to fix this (Either the documentation or adding the export from crypto to SSL).