SSL_get_current_cipher() and SSL_get_pending_cipher() return 'const SSL_CIPHER *'

Fix the documentation.

CLA: trivial

Reviewed-by: Matt Caswell <[email protected]>
Reviewed-by: Todd Short <[email protected]>
Reviewed-by: Paul Dale <[email protected]>
Reviewed-by: Tomas Mraz <[email protected]>
(Merged from openssl#18599)

Author: olszomal

doc/man3/SSL_get_current_cipher.pod

@@ -10,8 +10,8 @@ SSL_get_pending_cipher - get SSL_CIPHER of a connection
 
  #include <openssl/ssl.h>
 
- SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl);
- SSL_CIPHER *SSL_get_pending_cipher(const SSL *ssl);
+ const SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl);
+ const SSL_CIPHER *SSL_get_pending_cipher(const SSL *ssl);
 
  const char *SSL_get_cipher_name(const SSL *s);
  const char *SSL_get_cipher(const SSL *s);