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: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6067)
diff --git a/apps/s_client.c b/apps/s_client.c
index 89cddb3..9d463f6 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -637,7 +637,8 @@
      "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, '>',