Merge pull request 'docs-errata' (#3161) from docs-errata into main

Reviewed-on: https://git.clan.lol/clan/clan-core/pulls/3161

docs/site/manual/migration-guide.md

@@ -77,13 +77,18 @@ For the provide flake example, your flake should now look like this:
 ```nix
 {
   inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  
+  inputs.clan-core = {
+    url = "git+https://git.clan.lol/clan/clan-core";    
+    inputs.nixpkgs.follows = "nixpkgs";
+  };
 
-  outputs = { self, nixpkgs, ... }:
+  outputs = { self, nixpkgs, clan-core, ... }:
   let
     clan = clan-core.lib.buildClan {
         self = self; # this needs to point at the repository root
         specialArgs = {};
-        inventory.meta.name = "NEEDS_TO_BE_UNIQUE"; # TODO: Changeme
+        meta.name = throw "Change me to something unique";
 
         machines = {
             berlin = {
@@ -99,7 +104,12 @@ For the provide flake example, your flake should now look like this:
   in
   {
       nixosConfigurations = clan.nixosConfigurations;
+      
       inherit (clan) clanInternals;
+      
+      clan = {
+        inherit (clan) templates;
+      };
   };
 }
 ```

lib/inventory/build-inventory/meta-interface.nix

@@ -4,11 +4,14 @@ let
 
   metaOptions = {
     name = lib.mkOption {
-      type = types.str;
+      type = types.strMatching "[a-zA-Z0-9_-]*";
+      example = "my_clan";
       description = ''
         Name of the clan.
 
         Needs to be (globally) unique, as this determines the folder name where the flake gets downloaded to.
+
+        Should only contain alphanumeric characters, `_` and `-`.
       '';
     };
     description = lib.mkOption {