Update references to RFC's that the newer TFTP implementation supports.

usr.bin/tftp/tftp.1

@@ -217,6 +217,40 @@ Toggle packet tracing.
 .It Cm verbose
 Toggle verbose mode.
 .El
+.Sh SEE ALSO
+.Xr tftp 1
+.Pp
+The following RFC's are supported:
+.Rs
+RFC 1350
+.%T The TFTP Protocol (Revision 2)
+.Re
+.Rs
+RFC 2347
+.%T TFTP Option Extension
+.Re
+.Rs
+RFC 2348
+.%T TFTP Blocksize Option
+.Re
+.Rs
+RFC 2349
+.%T TFTP Timeout Interval and Transfer Size Options
+.Re
+.Rs
+RFC 3617
+.%T Uniform Resource Identifier (URI) Scheme and Applicability Statement for the Trivial File Transfer Protocol (TFTP) 
+.Re
+.Pp
+The non-standard
+.Cm rollover
+and
+.Cm blksize2
+TFTP options are mentioned here:
+.Rs
+.%T Extending TFTP
+.%U http://www.compuphase.com/tftp.htm
+.Re
 .Sh HISTORY
 The
 .Nm