a2248c87e2
The index description isn't right,
correct it as the Programmer's guide said.
Also correct the guide's figure description about 'Dequeue First Step'.
Fixes: 4a22e6ee3d2f ("doc: refactor figure numbers into references")
Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>