selftests/bpf: Fix spelling mistake "detecion" -> "detection"

There is a spelling mistake in a literal string. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230206092229.46416-1-colin.i.king@gmail.com

tools/testing/selftests/bpf/xdp_features.c

@@ -57,7 +57,7 @@ static void sig_handler(int sig)
 
 const char *argp_program_version = "xdp-features 0.0";
 const char argp_program_doc[] =
-"XDP features detecion application.\n"
+"XDP features detection application.\n"
 "\n"
 "XDP features application checks the XDP advertised features match detected ones.\n"
 "\n"