Update the Seed data article to include the new EF Core 9 UseSeeding and UseAsyncSeeding methods

[alistairmatthews]

Describe the issue or suggestion

Entity Framework Core 9 includes new methods for seeding data in a database: UseSeeding and UseAsyncSeeding. These are described in the EF Core Data Seeding article.

Update the Seed data using EF Core section of the Seed data in a database using .NET Aspire article to describe how to use these methods in an Aspire solution.