Tracking: DefaultValueComparer<T> API.

## Definition
````C#
public readonly struct DefaultValueComparer<T> : IComparer<T> where T : IComparable<T>
{
    public int Compare(T x, T y) => x.CompareTo(y);
}
````

## Implementation
- [x] Done.

## XML documentation
- [ ] Done.

## Proper documentation
- [ ] Done.