Add the following constructor to UnexpectedTokenException: public UnexpectedTokenException() (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1032)

NGramToken4 should override Equals (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1815)

NGramToken4 should override the equality (==) and inequality (!=) operators (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1815)

Add the following constructor to UnexpectedTokenException: public UnexpectedTokenException() (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1032)

Add the following constructor to UnexpectedTokenException: public UnexpectedTokenException(string message, Exception innerException) (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1032)

Properties should not return arrays (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1819)

Properties should not return arrays (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1819)

In externally visible method 'void WordTokenizer.AddStopWords(string[] stopWords)', validate parameter 'stopWords' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

Exception type System.Exception is not sufficiently specific (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2201)