Update README.markdown

Co-authored-by: Datong Sun <dndx@idndx.com>

Author: chronolaw

README.markdown

@@ -7747,7 +7747,7 @@ tcpsock:setclientcert
 **context:** *rewrite_by_lua*, access_by_lua*, content_by_lua*, ngx.timer.*, ssl_certificate_by_lua*, ssl_session_fetch_by_lua*, ssl_client_hello_by_lua**
 
 Set client certificate chain and corresponding private key to the TCP socket object.
-These certificate chain and private key will be used in the [tcpsock:sslhandshake](#tcpsocksslhandshake) method.
+The certificate chain and private key provided will be used later by the [tcpsock:sslhandshake](#tcpsocksslhandshake) method.
 
 * `cert` specify a client certificate chain cdata object that will be used while handshaking with
 remote server. These objects can be created using [ngx.ssl.parse\_pem\_cert](https://github.com/openresty/lua-resty-core/blob/master/lib/ngx/ssl.md#parse_pem_cert)