docs(guide/dev): remove some sections from CONTRIBUTING.md

Author: KSXGitHub

CONTRIBUTING.md

@@ -211,7 +211,6 @@ where
 ### Error Handling
 
 - Define custom error enums with `#[derive(Debug, Display, Error)]` from `derive_more`.
-- Mark error enums as `#[non_exhaustive]`.
 - Minimize `unwrap()` in non-test code — use proper error propagation. `unwrap()` is acceptable in tests and for provably infallible operations (with a comment explaining why). When deliberately ignoring an error, use `.ok()` with a comment explaining why.
 
 ```rust
@@ -223,22 +222,9 @@ pub enum RuntimeError {
 }
 ```
 
-### Documentation Comments
-
-- Use `///` doc comments for all public types, traits, functions, and fields.
-- Use `//!` module-level doc comments at the top of `lib.rs` and significant modules.
-- Include usage examples with `/// ```no_run` blocks for key public APIs.
-- Reference related types with `[`backtick links`](crate::path)` syntax.
-
-### Feature Gating
-
-- Use `#[cfg(feature = "...")]` for optional functionality (e.g., `json`, `cli`).
-- Use `#[cfg(unix)]` for POSIX-specific code.
-- Use `#[cfg_attr(feature = "json", derive(Deserialize, Serialize))]` for conditional derives.
-
 ### Pattern Matching
 
-Use exhaustive matching. When mapping enum variants to values, prefer the concise wrapping style:
+When mapping enum variants to values, prefer the concise wrapping style:
 
 ```rust
 ExitCode::from(match self {
@@ -255,10 +241,6 @@ Order fields logically by purpose, not alphabetically. Group related fields toge
 
 Use macros to reduce boilerplate for repetitive patterns (e.g. newtype wrappers, trait impls for multiple numeric types). Keep macros well-scoped and documented.
 
-### Warnings Policy
-
-The crate uses `#![deny(warnings)]` — all warnings are treated as errors. Code must compile warning-free.
-
 ## Setup
 
 Install the required Rust toolchain and components before running any checks: