Fix formatting in testpmd user guide for hairpin operation. Fixes: 01817b10d27c ("app/testpmd: change hairpin queues setup") Cc: stable@dpdk.org Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com> Acked-by: Xiaoyun Li <xiaoyun.li@intel.com> Reviewed-by: Bing Zhao <bingz@nvidia.com>