Docs/frontmatter: init automatic reference for frontmatter

lib/frontmatter/interface.nix

@@ -11,11 +11,16 @@ in
     description = mkOption {
       type = types.str;
       description = ''
-
+        A Short description of the module.
       '';
     };
     categories = mkOption {
       default = [ "Uncategorized" ];
+      description = ''
+        Categories are used for Grouping and searching.
+
+        While initial oriented on [freedesktop](https://specifications.freedesktop.org/menu-spec/latest/category-registry.html) the following categories are allowed
+      '';
       type = types.listOf (
         types.enum [
           "AudioVideo"
@@ -38,6 +43,15 @@ in
     };
     features = mkOption {
       default = [ ];
+      description = ''
+        Clans Features that the module implements support for.
+
+        !!! warning "Important"
+            Every ClanModule, that specifies `features = [ "inventory" ]` MUST have at least one role.
+            Many modules use `roles/default.nix` which registers the role `default`.
+
+            If you are a clan module author and your module has only one role where you cannot determine the name, then we would like you to follow the convention.
+      '';
       type = types.listOf (
         types.enum [
           "inventory"
@@ -47,6 +61,19 @@ in
 
     constraints = mkOption {
       default = { };
+      description = ''
+        Contraints for the module
+
+        The following example requires exactly one `server`
+        and supports up to `7` clients
+
+        ```md
+        ---
+        constraints.roles.server.eq = 1
+        constraints.roles.client.max = 7
+        ---
+        ```
+      '';
       type = types.submoduleWith {
         inherit specialArgs;
         modules = [