refactor!: add back Error trait

[tisonkun]

No description provided.

[Copilot]

Pull request overview

This pull request refactors the error handling system by introducing a custom Error trait that wraps std::error::Error + Send + Sync + 'static and provides a convenient raise method. This consolidates the trait bounds used throughout the codebase.

Changes:

• Introduces a new Error trait in lib.rs with a blanket implementation and a raise helper method
• Replaces all occurrences of std::error::Error + 'static with the custom Error trait
• Updates imports across all modules to use crate::Error instead of std::error::Error
• Adjusts documentation links and example line numbers to reflect the import changes

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
exn/src/lib.rs	Adds the new Error trait with blanket implementation and updates the Ok function signature
exn/src/impls.rs	Updates Exn and Frame to use the custom Error trait and fixes documentation links
exn/src/result.rs	Updates ResultExt trait bounds to use the custom Error trait
exn/src/option.rs	Updates import to use the custom Error trait
exn/src/display.rs	Updates import to use the custom Error trait
exn/src/debug.rs	Updates import to use the custom Error trait
examples/src/downcast.rs	Updates import and adjusts line numbers in output comments
examples/src/custom-layout.rs	Updates import to use the custom Error trait

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[tisonkun]

Closed in favor of considering #20.