Add analyzers introduced in .NET 7 to docs page

[captainsafia]

We added 4 new analyzers and codefixers in .NET 7. We need to document them over at https://docs.microsoft.com/en-us/aspnet/core/diagnostics/code-analysis?view=aspnetcore-6.0.

[captainsafia]

It turned out to be 7 analyzers but anyway they are all documented now.