improve documentation

sshdyndns

@@ -127,6 +127,9 @@ dnsupdate_tlsa [options] zone dnsname
 
 Print a brief help message and exits.
 
+=item B<-verbose>
+Show what's going on.
+
 =item B<-server>
 
 DNS server to send DNS updates to.
@@ -135,18 +138,22 @@ DNS server to send DNS updates to.
 
 DNS port to send DNS updates to, default 53.
 
+=item B<-tsigname>
+
+Name of the TSIG key.
+
+=item B<-tsigkey>
+
+Base64 encoding of the TSIG key.
+
+=item B<-tsigalgo>
+
+Algorithm of the TSGI key, default hmac-md5.
+
 =back
 
 =head 1 DESCRIPTION
 
-B<This program> will update A records.
-
-=head1 ENVIRONMENTS
-
-=item B<SSH_CLIENT>
-
-Remote IP to set A record to.
-
-=back
+B<This program> will update A records taken from the B<SSH_CLIENT> environment.
 
 =cut