feat(sys): impl Hash for ngx_str_t

[bavshin-f5]

Style fixes.

[Copilot]

Pull Request Overview

This PR implements Hash for ngx_str_t and applies style cleanups.

• Adds fmt::Display and hash::Hash trait implementations for ngx_str_t.
• Updates imports to use core::cmp, core::hash, and core::str, and simplifies namespace references.
• Removes duplicate Display impl and updates the TryFrom error alias to str::Utf8Error.

Comments suppressed due to low confidence (3)

nginx-sys/src/string.rs:116

• Public trait implementation is missing documentation; consider adding /// comments explaining how Display should format ngx_str_t.

impl fmt::Display for ngx_str_t {

nginx-sys/src/string.rs:132

• The new Hash implementation lacks doc comments; consider adding /// documentation to explain its behavior and guarantee for ngx_str_t.

impl hash::Hash for ngx_str_t {

nginx-sys/src/string.rs:132

• There are no unit tests for the new Hash implementation; consider adding tests to verify consistent hashing for identical and different ngx_str_t values.

impl hash::Hash for ngx_str_t {