minor improvements in -help message

lib/lv6MainArgs.ml

-(* Time-stamp: <modified the 26/02/2024 (at 16:24) by Erwan Jahier> *)
+(* Time-stamp: <modified the 19/04/2024 (at 10:01) by Erwan Jahier> *)
 (*
 Le manager d'argument adapt de celui de lutin, plus joli
 N.B. solution un peu batarde : les options sont stockes, comme avant, dans Global,
@@ -438,12 +438,12 @@ let mkoptab (opt:t) : unit = (
   mkopt opt ~doc_level:Advanced
     ["-lv4"; "--lustre-v4"]
     (Arg.Unit (fun _ -> set_v4_options opt))
-    ["deprecated: generate Lustre V4 code (force '-ei -ee -esa')"]
+    ["Generate Lustre V4 code (force '-ei -ee -esa')"]
   ;
   mkopt opt ~doc_level:Advanced
     ["-rte"; "--runtime-error"]
     (Arg.String (fun str -> global_opt.rte <- Some str; set_v4_options opt))
-    ["Experimental: Generate kind2 contracts to check for runtime errors (force '-lv4')"]
+    ["<string> Experimental: Generate kind2 contracts to check for runtime errors (force '-lv4')"]
   ;
   mkopt opt ~doc_level:Dev
     ["-kcg"; "--generate-scade-lustre"]
@@ -515,7 +515,7 @@ let mkoptab (opt:t) : unit = (
     ["-vl"]
     ~arg:" <int>"
     (Arg.Int(function i -> Lv6Verbose.set i))
-    ["Set the verbose level"]
+    ["<int> Set the verbose level"]
   ;
   mkopt opt
     ["-h";"-help";"--help"]
@@ -628,7 +628,7 @@ let mkoptab (opt:t) : unit = (
   mkopt opt ~doc_level:Advanced
     ["--precision"]
     (Arg.Int (fun i -> opt.precision <- Some i))
-    ["Number of digits after ther dot used to print floats in -exec mode"]
+    ["<int> Number of digits after ther dot used to print floats in -exec mode"]
   ;
   mkopt opt ~doc_level:Dev
     ["--nonreg-test"]