Doc: be explicit about NUL in max_identity_len
@@ -107,11 +107,11 @@ the pre-shared key to use during the connection setup phase.
The callback is set using functions SSL_CTX_set_psk_client_callback()
or SSL_set_psk_client_callback(). The callback function is given the
-connection in parameter B<ssl>, a B<NULL>-terminated PSK identity hint
+connection in parameter B<ssl>, a B<NUL>-terminated PSK identity hint
sent by the server in parameter B<hint>, a buffer B<identity> of
-length B<max_identity_len> bytes where the resulting
-B<NUL>-terminated identity is to be stored, and a buffer B<psk> of
-length B<max_psk_len> bytes where the resulting pre-shared key is to
+length B<max_identity_len> bytes (including the B<NUL>-terminator) where the
+resulting B<NUL>-terminated identity is to be stored, and a buffer B<psk>
+of length B<max_psk_len> bytes where the resulting pre-shared key is to
be stored.
The callback for use in TLSv1.2 will also work in TLSv1.3 although it is
