RoslynAnalyzers Use the 'StringComparison' method overloads to perform case-insensitive string comparisons

Avoid calling 'ToLower', 'ToUpper', 'ToLowerInvariant' and 'ToUpperInvariant' to perform case-insensitive string comparisons because they lead to an allocation. Instead, prefer calling the method overloads of 'Contains', 'IndexOf' and 'StartsWith' that take a 'StringComparison' enum value to perform case-insensitive comparisons. Switching to using an overload that takes a 'StringComparison' might cause subtle changes in behavior, so it's important to conduct thorough testing after applying the suggestion. Additionally, if a culturally sensitive comparison is not required, consider using 'StringComparison.OrdinalIgnoreCase'.