seccomp.2: SEE ALSO: add strace(1)

Point the reader at strace(1) as a way of discovering system calls
that might need to be filtered.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/seccomp.2

@@ -834,6 +834,7 @@ main(int argc, char **argv)
 }
 .EE
 .SH SEE ALSO
+.BR strace (1),
 .BR bpf (2),
 .BR prctl (2),
 .BR ptrace (2),