Add support for "first-class span types" C# language feature

[zgabi]

Since the latest Visual Studio version (17.13)/C# version some of our code started to fail at runtime.
The problem is that Microsoft implemeted the "First-class Span types" language feature (https://github.com/dotnet/csharplang/blob/main/proposals/first-class-span-types.md)
I'm using the LangVersion=preview settings (because of the "field" keyword)

For example we have the following code:

        var ids = new Guid[] { guid1, guid2... };
        foreach (var r in session.Query<MyClass>().Where(x => ids.Contains(x.Id)))
        {
            ...
        }
 

Earlier (before 11.02.2025) this code worked, but now it throws the following exception:

NHibernate.HibernateException
  HResult=0x80131500
  Message=Evaluation failure on op_Implicit(value(System.Guid[]))
  Source=NHibernate
  StackTrace:
   at NHibernate.Linq.Visitors.NhPartialEvaluatingExpressionVisitor.Visit(Expression expression)
....
Inner Exception 1:
NotSupportedException: Specified method is not supported.
 

Because earlier the predicate expression in the Where method was calling the Enumerable.Contains extension method, but now it calls the MemoryExtensions.Contains method.

There is a workaround:

        var ids = new Guid[] { guid1, guid2... };
        foreach (var r in session.Query<MyClass>().Where(x => ((IEnumerable<Guid>)ids).Contains(x.Id)))
        {
            ...
        }

but it needs to change our code everywhere. And hard to find every places since there is no build error, only a runtime exception.

[fredericDelaporte]

Another workaround, which would apply globally, would be to add custom generators for these MemoryExtensions methods, that would mimic the work of the standard generators.