The MSTEST0037 analyzer was not reporting diagnostics for Assert.IsFalse with string and collection methods, even though MSTest provides appropriate negative assertion methods for these cases.

Problem

Previously, these patterns would not trigger MSTEST0037:

Assert.IsFalse(myString.Contains("test"));     // No diagnostic
Assert.IsFalse(myString.StartsWith("Hello"));  // No diagnostic  
Assert.IsFalse(myString.EndsWith("World"));    // No diagnostic
Assert.IsFalse(myList.Contains(item));         // No diagnostic

Solution

The analyzer now detects these patterns and suggests the appropriate negative assertion methods:

// Before: No diagnostics
Assert.IsFalse(myString.Contains("test"));
Assert.IsFalse(myString.StartsWith("Hello"));
Assert.IsFalse(myString.EndsWith("World"));
Assert.IsFalse(myList.Contains(item));

// After: MSTEST0037 diagnostics with code fixes
Assert.DoesNotContain("test", myString);
Assert.DoesNotStartWith("Hello", myString);  
Assert.DoesNotEndWith("World", myString);
Assert.DoesNotContain(item, myList);

Changes Made

1. Analyzer Enhancement: Modified UseProperAssertMethodsAnalyzer.AnalyzeIsTrueOrIsFalseInvocation to handle IsFalse cases with string and collection methods
2. Documentation Update: Updated XML documentation to include the new supported patterns
3. Test Coverage: Added comprehensive tests for all new diagnostic patterns with expected code fixes
4. Backward Compatibility: All existing functionality remains unchanged

The implementation leverages the existing CodeFixModeAddArgument infrastructure, so code fixes work seamlessly with the new patterns.

Fixes #6177.

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