[3.8] Document missing methods of ssl.SSLObject (GH-19400)

[miss-islington]

Co-authored-by: Rémi Lapeyre remi.lapeyre@lenstra.fr
(cherry picked from commit 74e1b6b)

Co-authored-by: Rémi Lapeyre remi.lapeyre@henki.fr

[miss-islington]

@remilapeyre and @tiran: Status check is done, and it's a failure ❌ .

[csabella]

@tiran, @remilapeyre, is this just waiting for the approval to finish the backport? Thanks!

[remilapeyre]

@tiran I think this PR is ready to be merged :)

[tiran]

CI is failing :(

[remilapeyre]

It looks like it's failing for an unrelated change:

/Users/remi/src/cpython/Doc/c-api/buffer.rst:92:Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name. [error at 5]
  void \*buf
  -----^
make[1]: *** [build] Error 2
Suspicious check complete; look for any errors in the above output or in build/suspicious/suspicious.csv.  If all issues are false positives, append that file to tools/susp-ignored.csv.

It has since been fixed and merging origin/3.8 in this branch fixes the issue but I don't think I can push on this PR to fix it thought.

Edit: yes, it was fixed in 37a257c