curl.1: -E: s/private certificate/client certificate

... as the certificate is strictly speaking not private.

Reported-by: John Levon

docs/curl.1

@@ -488,10 +488,10 @@ If this option is used several times, the last one will be used.
 (SSL) Tells curl to use the specified client certificate file when getting a
 file with HTTPS, FTPS or another SSL-based protocol. The certificate must be
 in PKCS#12 format if using Secure Transport, or PEM format if using any other
-engine.  If the optional password isn't specified, it will be queried
-for on the terminal. Note that this option assumes a \&"certificate" file that
-is the private key and the private certificate concatenated! See \fI--cert\fP
-and \fI--key\fP to specify them independently.
+engine.  If the optional password isn't specified, it will be queried for on
+the terminal. Note that this option assumes a \&"certificate" file that is the
+private key and the client certificate concatenated! See \fI--cert\fP and
+\fI--key\fP to specify them independently.
 
 If curl is built against the NSS SSL library then this option can tell
 curl the nickname of the certificate to use within the NSS database defined