Clarify use of relative paths in benching

Mixing abs/rel paths is error prune due to multiple shell configs.
Maintain current expected relative paths only. But add the note to comments and help text on bench scripts

Client/bench.py

@@ -20,8 +20,8 @@
 
 # The sole purpose of this module is to invoke run_benchmark().
 #
-#   - binary   : Path to, and including, the Binary File
-#   - network  : Path to Network File, or None
+#   - binary   : Relative path to, and including, the Binary File
+#   - network  : Relative path to a private engine's Network File, or None
 #   - private  : True or False; Private NNUE engines require special care
 #   - threads  : Number of concurrent benches to run
 #   - sets     : Number of times to repeat this experiment

Scripts/bench_engine.py

@@ -33,10 +33,10 @@
 if __name__ == '__main__':
 
     p = argparse.ArgumentParser()
-    p.add_argument('-E', '--engine'  , help='Binary Name',                  required=True)
-    p.add_argument('-N', '--network' , help='Networks for Private Engines', required=False)
-    p.add_argument('-T', '--threads' , help='Concurrent Benchmarks',        required=True, type=int)
-    p.add_argument('-S', '--sets'    , help='Benchmark Sample Count',       required=True, type=int)
+    p.add_argument('-E', '--engine'  , help='Relative path to Binary', required=True)
+    p.add_argument('-N', '--network' , help='Relative path to Network for Private Engines', required=False)
+    p.add_argument('-T', '--threads' , help='Concurrent Benchmarks', required=True, type=int)
+    p.add_argument('-S', '--sets'    , help='Benchmark Sample Count', required=True, type=int)
     args = p.parse_args()
 
     private = args.network != None