less: migrate to lib.cli.toCommandLineGNU

Migrates from the deprecated toCommandLine to toCommandLineGNU.

This changes the output format to use GNU-style options with equals
(--wheel-lines=3). Both formats were verified to work correctly with less.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

modules/programs/less.nix

@@ -45,7 +45,7 @@ in
             ];
             attrs = attrsOf (either scalar (listOf scalar));
           in
-          coercedTo attrs (lib.cli.toGNUCommandLine { }) (listOf str);
+          coercedTo attrs (lib.cli.toCommandLineGNU { }) (listOf str);
         default = [ ];
         description = "Options to be set via {env}`$LESS`.";
         example = {