Fix documentation for the -showcerts s_client option

This option shows the certificates as sent by the server. It is not the
full verified chain.

Fixes #4933
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6067)

apps/s_client.c

@@ -637,7 +637,8 @@ const OPTIONS s_client_options[] = {
      "Disable name checks when matching DANE-EE(3) TLSA records"},
     {"reconnect", OPT_RECONNECT, '-',
      "Drop and re-make the connection with the same Session-ID"},
-    {"showcerts", OPT_SHOWCERTS, '-', "Show all certificates in the chain"},
+    {"showcerts", OPT_SHOWCERTS, '-',
+     "Show all certificates sent by the server"},
     {"debug", OPT_DEBUG, '-', "Extra output"},
     {"msg", OPT_MSG, '-', "Show protocol messages"},
     {"msgfile", OPT_MSGFILE, '>',

doc/man1/s_client.pod

@@ -333,8 +333,9 @@ be used as a test that session caching is working.
 
 =item B<-showcerts>
 
-Display the whole server certificate chain: normally only the server
-certificate itself is displayed.
+Displays the server certificate list as sent by the server: it only consists of
+certificates the server has sent (in the order the server has sent them). It is
+B<not> a verified chain.
 
 =item B<-prexit>
 
@@ -695,7 +696,8 @@ a client certificate. Therefor merely including a client certificate
 on the command line is no guarantee that the certificate works.
 
 If there are problems verifying a server certificate then the
-B<-showcerts> option can be used to show the whole chain.
+B<-showcerts> option can be used to show all the certificates sent by the
+server.
 
 The B<s_client> utility is a test tool and is designed to continue the
 handshake after any certificate verification errors. As a result it will