man: add missing -c option to tcpretrans synopsis
.SH NAME
tcpretrans \- Trace or count TCP retransmits and TLPs. Uses Linux eBPF/bcc.
.SH SYNOPSIS
-.B tcpretrans [\-h] [\-l]
+.B tcpretrans [\-h] [\-l] [\-c]
.SH DESCRIPTION
This traces TCP retransmits, showing address, port, and TCP state information,
and sometimes the PID (although usually not, since retransmits are usually
