MA0002: treat the xunit assertions that take an IEqualityComparer<T> as ordinal with report_only_non_ordinal

[vencyk]

With MA0002.report_only_non_ordinal = true, a call to a Xunit.Assert method is no longer reported when the overload it lacks takes an IEqualityComparer<string>: Equal, NotEqual, Contains, DoesNotContain and Distinct. This mirrors the existing special case for Meziantou.Framework.Assertions.Assert.

Why: xunit compares strings ordinally, in its own Assert.Equal(string, string) overloads and, for items and collections, through IEquatable<string>. In a test project with the option on, Assert.Equal(expectedStrings, actualStrings) and Assert.Contains("a", strings) were the only calls left reported, and passing StringComparer.Ordinal to them changes nothing.

What stays reported: a method whose missing overload takes an IComparer<string> (InRange, NotInRange), since Comparer<string>.Default is culture-sensitive. The check is on the comparer kind of the overload, not on method names.

Tests: four added to UseStringComparerAnalyzerTests. The equality assertions are tested against the real xunit v3 and v2 packages (AddXunitV3() / AddXunitV2()). The ordering test uses a stub Xunit.Assert, because the overload finder does not detect the real generic InRange<T> overload today; that gap is independent of this change. UseStringComparerAnalyzerTests passes on Roslyn 5.9 (91 tests) and Roslyn 4.8 (67 tests). dotnet run --project src/DocumentationGenerator was run; the only documentation change is the note in docs/Rules/MA0002.md.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The implementation and tests cover the requested behavior; only a non-blocking documentation nit remains.

1 open finding

• Fix unmatched closing parenthesis in configuration example · New

What changed in this PR

Updates MA0002 to treat xUnit equality-comparer assertions as ordinal when report_only_non_ordinal is enabled.

Changes:

• Added xUnit v2/v3 comparer handling.
• Added equality and ordering tests.
• Updated MA0002 documentation.

File	Summary
tests/​Meziantou.Analyzer.Test/​Rules/​UseStringComparerAnalyzerTests.cs	Adds xUnit behavior coverage.
src/​Meziantou.Analyzer/​Rules/​UseStringComparerAnalyzer.cs	Handles xUnit assertion comparer overloads.
docs/​Rules/​MA0002.md	Documents the new behavior; includes a minor punctuation nit.

🧠 Review effort: Lite

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