bpftool: Add HELP_SPEC_OPTIONS in token.c

$ ./bpftool token help

Usage: bpftool token { show | list }
bpftool token help
OPTIONS := { {-j|--json} [{-p|--pretty}] | {-d|--debug} }

Fixes: 2d812311c2b2 ("bpftool: Add bpf_token show")
Signed-off-by: Tao Chen <[e-mail]>
Signed-off-by: Andrii Nakryiko <[e-mail]>
Acked-by: Quentin Monnet <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/bpf/bpftool/token.c

···
 	fprintf(stderr,
 		"Usage: %1$s %2$s { show | list }\n"
 		"       %1$s %2$s help\n"
+		"       " HELP_SPEC_OPTIONS " }\n"
 		"\n"
 		"",
 		bin_name, argv[-2]);