tls13-ciphers.d: shorten the Arg
diff --git a/docs/cmdline-opts/tls13-ciphers.d b/docs/cmdline-opts/tls13-ciphers.d
index 654a25b..db80335 100644
--- a/docs/cmdline-opts/tls13-ciphers.d
+++ b/docs/cmdline-opts/tls13-ciphers.d
@@ -1,5 +1,5 @@
 Long: tls13-ciphers
-Arg: <list of TLS 1.3 ciphersuites>
+Arg: <ciphersuite list>
 help: TLS 1.3 cipher suites to use
 Protocols: TLS
 ---