Fix/new code err with msg

[fmyAgi7]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @fmyAgi7, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the error handling system by refining how error messages are formatted for better readability and correctness, and by ensuring that debug output is routed to the appropriate standard error stream. Additionally, it includes a new test to validate these improvements and cleans up an outdated dependency configuration.

Highlights

• Improved Error Message Formatting: The NewCodeErrWithMsg function now utilizes golang.org/x/text/cases for more accurate and locale-aware title casing of error messages, replacing the less robust strings.ToTitle.
• Debug Output Redirection: The Debug function has been updated to direct its output to os.Stderr instead of os.Stdout, which is the conventional stream for diagnostic and error information.
• New Test Case for Error Messages: A new test, TestNewCodeErrWithMsg, has been added to ensure the correct title casing behavior of error messages generated by NewCodeErrWithMsg.
• Dependency Cleanup: An unnecessary replace directive for github.com/ugorji/go/codec has been removed from the go.mod file, streamlining the project's dependencies.

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[gemini-code-assist]

Code Review

This pull request correctly replaces the deprecated strings.ToTitle with cases.Title and redirects debug error output to stderr. The changes are positive and improve the codebase. I've added a couple of comments: one to improve performance by reusing the caser instance, and another to make the new test more robust by properly handling the return value of errors.As to prevent potential panics.

[gemini-code-assist]

The test should check the boolean return value of errors.As instead of just logging it. If errors.As fails, err2 will be nil, and the subsequent call to err2.Error() on the next line will cause a panic, making the test fragile.

if !errors.As(err1, �&err2) {
	t.Fatal("errors.As failed to cast to *errors.ErrCode")
}

[gemini-code-assist]

Creating a caser with cases.Title is a relatively expensive operation. The documentation for golang.org/x/text/cases recommends creating it once and reusing it. To improve performance, consider defining this caser as a package-level variable to avoid creating it on every function call.