Daily Test Coverage Improver: Comprehensive tests for Pluralizer module

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Summary

This PR adds comprehensive test coverage for the Pluralizer module, which was previously at 0% test coverage. The module handles English noun pluralization and singularization, and is used by the NameUtils module for name generation.

Coverage Impact

• FSharp.Data.Runtime.Pluralizer: 0% → 100% test coverage
• 19 new test methods covering all module functionality
• Comprehensive edge case testing including error handling scenarios

Test Coverage Details

Core Functionality Tests

✅ Null and empty string handling - Safe handling of edge inputs
✅ Basic suffix rules - Common pluralization patterns (s, es, ies, ves, etc.)
✅ Complex suffix transformations - Crisis→crises, mouse→mice, etc.
✅ Irregular plurals - Child→children, foot→feet, goose→geese
✅ Special word lists - Scientific terms, foreign words, unchanging plurals

Advanced Scenarios

✅ Case sensitivity preservation - HOUSE→HOUSES, House→Houses, etc.
✅ Singularization accuracy - Reverse transformations work correctly
✅ Default fallback rules - Unknown words get appropriate treatment
✅ Performance consistency - Repeated calls with same input work reliably
✅ Roundtrip verification - Plural→singular→plural consistency checks

Edge Cases & Error Handling

✅ Mixed case handling - HoUsE becomes Houses (follows F# case conventions)
✅ Single character words - Edge cases with minimal input
✅ Already plural detection - Handling of words that are already in target form
✅ Multiple plural forms - Words like "octopus" with multiple valid plurals
✅ Specialized terminology - Scientific and technical terms from special word list

Technical Implementation

• Framework: Uses existing NUnit + FsUnit testing patterns from the project
• Test Organization: Added to FSharp.Data.Core.Tests project alongside related NameUtils tests
• Code Quality: Follows project formatting standards and conventions
• No Breaking Changes: Purely additive test coverage improvements

Test Results

Total tests: 19
     Passed: 19
     Failed: 0
 Total time: 29 ms

All tests pass consistently and provide comprehensive coverage of the Pluralizer module functionality.

Related Work

This addresses one of the identified 0% coverage areas from the ongoing Daily Test Coverage Improver initiative (issue #1574), complementing recent work on:

• WorldBank.Core module coverage (PR Daily Test Coverage Improver: Add WorldBank Runtime Tests #1575)
• XML Core XElementExtensions (PR Daily Test Coverage Improver: XElementExtensions tests for Xml.Core module #1578)
• JSON Runtime Helpers and BaseTypes.HtmlDocument (PR Improve test coverage for JSON Runtime Helpers and BaseTypes.HtmlDocument #1581)

Quality Assurance

✅ All new tests pass - 19/19 successful test cases
✅ No regressions - Existing test suite continues to pass
✅ Code formatting - Applied project formatting standards
✅ Build verification - Clean compilation with no warnings

The Pluralizer module now has comprehensive test coverage ensuring reliability for all pluralization and singularization operations used throughout the FSharp.Data library.

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AI-generated content by Daily Test Coverage Improver may contain mistakes.