Remove clippy pedantic and nursery lints by default

Mention how to run them in CONTRIBUTING

CONTRIBUTING.md

@@ -17,11 +17,18 @@ The most important tools and commands in this environment are:
   ```bash
   cargo test
   ```
-- Linting and formatting:
+- Formatting:
   ```bash
-  cargo clippy --all-targets
   treefmt
   ```
+- Linting:
+  ```bash
+  cargo clippy --all-targets
+  ```
+  Or optionally:
+  ```bash
+  cargo clippy --all-targets -- -W clippy::nursery -W clippy::pedantic
+  ```
 - Running the [main CI checks](./.github/workflows/main.yml) locally:
   ```bash
   nix-build -A ci

src/main.rs

@@ -1,8 +1,3 @@
-#![warn(clippy::pedantic, clippy::nursery)]
-// too many false-positives. discussion:
-// https://github.com/NixOS/nixpkgs-vet/pull/124#pullrequestreview-2405109643
-#![allow(clippy::module_name_repetitions)]
-
 mod eval;
 mod location;
 mod nix_file;