update contributing guide and format repo

.vscode/extensions.json

@@ -0,0 +1,6 @@
+{
+  "recommendations": [
+    "EditorConfig.EditorConfig",
+    "mkhl.direnv"
+  ]
+}

CONTRIBUTING.md

@@ -1,25 +1,47 @@
 # Contributing
 
+Thanks for your interest in contributing!
+We welcome ideas, code, docs, etc -- just open an issue or MR.
+
+## Setup
+
+This project uses [flakes](https://nixos.wiki/wiki/Flakes) so a development environment can be created with
+
+    nix develop
+
+where you will find a [devshell](https://numtide.github.io/devshell) prompt (which supports [direnv](https://direnv.net/) so a one-time `direnv allow` at the base of the repo should automate the dev shell process).
+
+## Commits
+
+There's no formal commit process at this time.
+
+Do try to format the repo before submission, however.
+
+    nix develop -c treefmt
+
 ## Kubernetes versions
 
-Edit [`./jobs/generators/default.nix`](./jobs/generators/default.nix) and add a block for the new version of Kubernetes in `generate.k8s`. For example:
+To support a new Kubernetes version:
 
-```nix
+- Edit [`./jobs/generators/default.nix`](./jobs/generators/default.nix) and add a block for the version under `k8s`; for example:
-{
+
+  ```nix
+  {
     name = "v1.23.nix";
     path = generateK8S "v1.23" (builtins.fetchurl {
       url = "https://github.com/kubernetes/kubernetes/raw/v1.23.0/api/openapi-spec/swagger.json";
       sha256 = "0jivg8nlxka1y7gzqpcxkmbvhcbxynyrxmjn0blky30q5064wx2a";
     });
-}
+  }
-```
+  ```
 
-Then build and copy all specs to [`modules/generated/`](./modules/generated/):
+- Build and copy the updated specs to [`modules/generated/`](./modules/generated/)
 
       nix build '.#jobs.x86_64-linux.generators.k8s'
       cp ./result/* modules/generated/
 
-Now add the version in [`./modules/k8s.nix`](./modules/k8s.nix) under `options.kubernetes.version.type` as well as a new check in [`./flake.nix`](./flake.nix) (e.g., `tests-k8s-1_23`).
+- Add the version in [`./modules/k8s.nix`](./modules/k8s.nix) under `options.kubernetes.version.type`
+- Add a new check in [`./flake.nix`](./flake.nix) (e.g., `tests-k8s-1_23`)
 
 ## Tests
 

flake.nix

@@ -61,7 +61,8 @@
                     };
                   }
                 ];
-              specialArgs = {inherit kubenix;
+              specialArgs = {
+                inherit kubenix;
                 inherit pkgs;
               };
             }

modules/k8s.nix

@@ -282,7 +282,6 @@ in {
       default = null;
     };
 
-
     customResources = mkOption {
       description = "Setup custom resources";
       type = types.listOf types.attrs;