Add missing 'type', 'defaultText' and 'literalExample' in module definitions

- add missing types in module definitions
- add missing 'defaultText' in module definitions
- wrap example with 'literalExample' where necessary in module definitions

nixos/modules/config/shells-environment.nix

@@ -119,6 +119,7 @@ in
 
     environment.binsh = mkOption {
       default = "${config.system.build.binsh}/bin/sh";
+      defaultText = "\${config.system.build.binsh}/bin/sh";
       example = literalExample ''
         "''${pkgs.dash}/bin/dash"
       '';