Better heuristics for if a disposable is created

[JohanLarsson]

For binary references where we can't walk the source we need to make a best guess about if a method returns a new instance that we now own and should dispose.

public static class Extensions
{
    /// <summary>
    /// Test method that returns a different type than the in parameter. We assume that the method creates a new disposable then.
    /// </summary>
    public static ICustomDisposable AsCustom(this IDisposable disposable) => default(ICustomDisposable);

    /// <summary>
    /// Test method that returns the same type as the in parameter. We assume that the method does not create a new disposable then.
    /// </summary>
    public static IDisposable Fluent(this IDisposable disposable) => disposable;
}

[JohanLarsson]

There are more cases we should list.

[JohanLarsson]

#126