SyntaxGenerator crashes with 'checked' operators

[Youssef1313]

on main branch, adding a test to SyntaxGeneratorTests.cs:

        [Fact]
        public void Test()
        {
            var comp = CSharpCompilation.Create(null, new[] { SyntaxFactory.ParseSyntaxTree("""
                public class C
                {
                    public static C operator checked ++(C x) => x;
                }
                """) });
            var operatorSymbol = (IMethodSymbol)comp.GetTypeByMetadataName("C").GetMembers(WellKnownMemberNames.CheckedIncrementOperatorName).Single();
            VerifySyntax<OperatorDeclarationSyntax>(Generator.OperatorDeclaration(operatorSymbol), "");
        }

crashes with

System.ArgumentException : Unknown operator kind.

  Stack Trace: 
    SyntaxGenerator.GetOperatorKind(IMethodSymbol method) line 256
    SyntaxGenerator.OperatorDeclaration(IMethodSymbol method, IEnumerable`1 statements) line 215
    SyntaxGeneratorTests.Test() line 3791