Revert "nixos: doc: implement related packages in the manual"

lib/options.nix

@@ -14,7 +14,6 @@ rec {
     , defaultText ? null # Textual representation of the default, for in the manual.
     , example ? null # Example value used in the manual.
     , description ? null # String describing the option.
-    , relatedPackages ? null # Related packages used in the manual.
     , type ? null # Option type, providing type-checking and value merging.
     , apply ? null # Function that converts the option value to something else.
     , internal ? null # Whether the option is for NixOS developers only.
@@ -77,6 +76,7 @@ rec {
   getValues = map (x: x.value);
   getFiles = map (x: x.file);
 
+
   # Generate documentation template from the list of option declaration like
   # the set generated with filterOptionSets.
   optionAttrSetToDocList = optionAttrSetToDocList' [];
@@ -93,10 +93,9 @@ rec {
           readOnly = opt.readOnly or false;
           type = opt.type.description or null;
         }
-        // optionalAttrs (opt ? example) { example = scrubOptionValue opt.example; }
-        // optionalAttrs (opt ? default) { default = scrubOptionValue opt.default; }
-        // optionalAttrs (opt ? defaultText) { default = opt.defaultText; }
-        // optionalAttrs (opt ? relatedPackages && opt.relatedPackages != null) { inherit (opt) relatedPackages; };
+        // (if opt ? example then { example = scrubOptionValue opt.example; } else {})
+        // (if opt ? default then { default = scrubOptionValue opt.default; } else {})
+        // (if opt ? defaultText then { default = opt.defaultText; } else {});
 
         subOptions =
           let ss = opt.type.getSubOptions opt.loc;