[Rust] Replace more HeaderValue::from_str with compile time from_static

[andrzejressel]

This pull requests replace more instances of HeaderValue::from_str with HeaderValue::from_static.

@frol @farcaller @richardwhiuk @paladinzh @jacob-pro @dsteeley

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[Copilot]

Pull Request Overview

This pull request replaces more instances of HeaderValue::from_str with HeaderValue::from_static for compile-time string values in Rust-generated code. This optimization removes unnecessary runtime string validation since the header values are known at compile time.

• Replaces HeaderValue::from_str() with HeaderValue::from_static() for static header values
• Updates Mustache templates to generate more efficient code
• Includes minor import ordering improvements for consistency

Reviewed Changes

Copilot reviewed 53 out of 53 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
samples/server/petstore/rust-server/output/*/src/server/mod.rs	Replace HeaderValue::from_str() calls with static variants for Content-Type headers
samples/server/petstore/rust-server/output/*/src/client/mod.rs	Replace dynamic header creation with static variants for known media types
samples/server/petstore/rust-axum/output/*/src/server/mod.rs	Replace HeaderValue::from_str() with static variants in Axum implementations
samples/server/petstore/rust-axum/output/*/src/types.rs	Minor import ordering improvements for consistency
modules/openapi-generator/src/main/resources/rust-server/*.mustache	Update Mustache templates to generate static header values

[dsteeley]

Thanks for submitting this. You've not mentioned why you've removed the error context on some of the responses. Could you explain that decision.
My understanding is that this is a breaking change to the response in some error scenarios.

[andrzejressel]

Thanks for submitting this. You've not mentioned why you've removed the error context on some of the responses. Could you explain that decision. My understanding is that this is a breaking change to the response in some error scenarios.

Sure, error handling was there, because HeaderValue::from_str returns Result - after all, string to header conversion may fail. But from_static performs it in compile time - so the error will happen during compilation. From runtime point of view - value is already valid.

[wing328]

the change sounds reasonable to me

let's give it a try