Immutable classes should hide default ctor analyzer

public class ConflictProperties {
public ConflictProperties();
public string Id { get; }
public OperationKind OperationKind { get; }
}

These are immutable yet have a public default ctor.

No files, tests, or entry points are named. Start by locating the analyzer that handles immutable classes and reproduce the issue with the ConflictProperties declaration; done means the analyzer correctly handles its public default constructor.

Written by the indexing model from the issue text.