[docs] Correct typos in SSLContext.sni_callback (GH-30623) (GH-31421)

Co-authored-by: Jörn Heissler <nosuchaddress@joern-heissler.de>
(cherry picked from commit f80a97b492f41afd3c42bb2bd6da7b2828dca215)

Co-authored-by: Jörn Heissler <joernheissler@users.noreply.github.com>
1 file changed