[vpr][route][lookahead] fix comment to show that the second index in wire_cost_map index is target layer

Author: amin1377

vpr/src/route/router_lookahead_map.h

@@ -47,9 +47,9 @@ class MapLookahead : public RouterLookahead {
 // To store this information, the first index is the layer number that the node under consideration is on, the second index represents the type of channel (X/Y)
 // that the node under consideration belongs to, the third is the segment type (specified in the architecture file under the "segmentlist" tag), the fourth is the
 // target "layer_num" mentioned above, the fifth is dx, and the last one is dy.
-typedef vtr::NdMatrix<util::Cost_Entry, 6> t_wire_cost_map; //[0..num_layers][0..1][[0..num_seg_types-1][0..num_layers][0..device_ctx.grid.width()-1][0..device_ctx.grid.height()-1]
+typedef vtr::NdMatrix<util::Cost_Entry, 6> t_wire_cost_map; //[0..num_layers][0..num_layers][0..1][[0..num_seg_types-1][0..device_ctx.grid.width()-1][0..device_ctx.grid.height()-1]
                                                             //[0..1] entry distinguish between CHANX/CHANY start nodes respectively
-                                                            // The first index is the layer number that the node under consideration is on, and the forth index
+                                                            // The first index is the layer number that the node under consideration is on, and the second index
                                                             // is the layer number that the target node is on.
 
 void read_router_lookahead(const std::string& file);