Remove reference to DIR as there is no actual support for it.

src/main.ml

@@ -102,20 +102,8 @@ let exec_cmd cmdname cmd =
 
 let config_cmd =
   let cmdname = "config" in
-  let dirvar = "DIR" in
-  let envs =
-    [
-      Term.env_info
-        ~doc:
-          "Absolute path to the directory containing the executable of a \
-           solver."
-        dirvar;
-    ]
-  in
   let detect =
-    let doc =
-      Fmt.str "Detect solvers in \\$PATH (or \\$%s, if specified)." dirvar
-    in
+    let doc = "Detect solvers in \\$PATH." in
     Arg.(value & flag & info [ "d"; "detect" ] ~doc)
   in
   let doc = Fmt.str "%s configuration." caisar in
@@ -136,7 +124,7 @@ let config_cmd =
                 as soon as other options are available. *)
              `Ok (exec_cmd cmdname (fun () -> config true ())))
         $ detect $ setup_logs)),
-    Term.info cmdname ~sdocs:Manpage.s_common_options ~envs ~exits ~doc ~man )
+    Term.info cmdname ~sdocs:Manpage.s_common_options ~exits ~doc ~man )
 
 let verify_cmd =
   let cmdname = "verify" in