Add missing options to authid show man page
@@ -50,6 +50,11 @@ OPTIONS
: Specifies the URL for the `splinterd` REST API. The URL is required unless
`$SPLINTER_REST_API_URL` is set.
+`--id-user` USER-ID
+: A public key identity to show
+
+`--id-key` PUBLIC-KEY
+: A public key identity to show
EXAMPLES
========
