add help message for --router_initial_acc_cost_chan_congestion_threshold and --router_initial_acc_cost_chan_congestion_weight

Author: soheilshahrouz

vpr/src/base/read_options.cpp

@@ -2889,12 +2889,16 @@ argparse::ArgumentParser create_arg_parser(const std::string& prog_name, t_optio
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     route_timing_grp.add_argument<double>(args.router_initial_acc_cost_chan_congestion_threshold, "--router_initial_acc_cost_chan_congestion_threshold")
-        .help("help message")
+        .help("Utilization threshold above which initial accumulated routing cost (acc_cost) "
+              "is increased to penalize congested channels. Used to bias routing away from "
+              "highly utilized regions during early routing iterations.")
         .default_value("100.0")
         .show_in(argparse::ShowIn::HELP_ONLY);
 
     route_timing_grp.add_argument<double>(args.router_initial_acc_cost_chan_congestion_weight, "--router_initial_acc_cost_chan_congestion_weight")
-        .help("help message")
+        .help("Weight applied to the excess channel utilization (above threshold) "
+              "when computing the initial accumulated cost (acc_cost)of routing resources. "
+              "Higher values make the router more sensitive to early congestion.")
         .default_value("1.0")
         .show_in(argparse::ShowIn::HELP_ONLY);