extend assert functions by add fail_msg~ argument

[myfreess]

use case: calling assert_true/assert_false in for loop unicode test

[peter-jerry-ye-code-review]

Inconsistent string interpolation usage in default messages

Category
Maintainability
Code Snippet
fail_msg~ : String = "\{debug_string(a)} != \{debug_string(b)}"
Recommendation
Consider using consistent string formatting across all assertions. For assert_true/false, consider using debug_string(x) like other assertions
Reasoning
The assertion functions use different string formatting approaches. assert_eq/not_eq use debug_string while assert_true/false directly interpolate the value. Using debug_string consistently would provide better formatted output especially for complex types.

Redundant string conversion removed but behavior changed

Category
Correctness
Code Snippet
if x {
fail(fail_msg, loc~)
}
Recommendation
Consider keeping the debug_string conversion in the default message:
fail_msg~ : String = "{debug_string(x)} is not false"
Reasoning
The original code explicitly converted the boolean to string using debug_string. The new version may produce different output for the default message, potentially breaking existing tests that depend on the exact error message format.

Documentation needs update to reflect new parameter

Category
Maintainability
Code Snippet
/// # Examples
/// /// assert_true(1 == 1) ///
Recommendation
Update documentation to include examples of custom failure messages:

/// # Examples
/// ```
/// assert_true(1 == 1)
/// assert_true(1 == 1, "Custom error message")
/// ```

**Reasoning**
The documentation examples don't show the new fail_msg parameter usage. Adding examples would help users understand how to use the new functionality.

</details>

[coveralls]

Pull Request Test Coverage Report for Build 7009

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 92.521%

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Totals
Change from base Build 7006:	0.0%
Covered Lines:	8746
Relevant Lines:	9453

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💛 - Coveralls

[peter-jerry-ye]

Why the default is empty