mention SSL_do_handshake()

doc/ssl/SSL_get_error.pod

@@ -13,7 +13,7 @@ SSL_get_error - obtain result code for TLS/SSL I/O operation
 =head1 DESCRIPTION
 
 SSL_get_error() returns a result code (suitable for the C "switch"
-statement) for a preceding call to SSL_connect(), SSL_accept(),
+statement) for a preceding call to SSL_connect(), SSL_accept(), SSL_do_handshake(),
 SSL_read(), SSL_peek(), or SSL_write() on B<ssl>.  The value returned by
 that TLS/SSL I/O function must be passed to SSL_get_error() in parameter
 B<ret>.