Enhance matrix tests documentation

[koryphaee]

Explain matrix behaviour for bool/enum as requested in #5187 (reply in thread).

Description

[Matrix] has a special behaviour when used with bool / enum which was undocumented. This PR documents it in an info box.

Related Issue

#5187

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Performance improvement
• Refactoring (no functional changes)

Checklist

Required

• I have read the Contributing Guidelines
• If this is a new feature, I started a discussion first and received agreement
• My code follows the project's code style (modern C# syntax, proper naming conventions)
• I have written tests that prove my fix is effective or my feature works

[greptile-apps]

Greptile Summary

The PR documents the existing parameterless [Matrix] behavior for boolean and enum parameters.

• Adds an info callout explaining that known values are expanded automatically.

Confidence Score: 5/5

The documentation-only change appears safe to merge.

The new statement matches the existing matrix implementation, which expands parameterless boolean matrices to both values and enum matrices to their defined values.

Important Files Changed

Filename	Overview
docs/docs/writing-tests/matrix-tests.md	Adds a concise and implementation-consistent explanation of automatic boolean and enum value expansion.

_{Reviews (1): Last reviewed commit: "Enhance matrix tests documentation" | Re-trigger Greptile}

[thomhurst]

Thanks!

[koryphaee]

Damn you're fast. Thanks for making this great library. I'm happy I could help improve it a tiny bit.