Namespace of generated code not detected

# Issue

We have a source code generator generating code in a defined namespace

```csharp
namespace Path.To.My.Generated.Code;

public static class MyGeneratedClass
{
..
}
```

and we are consumig that generator in a different assembly

```
using Path.To.My.Generated.Code;

var field = MyGeneratedClass.Field;
```
when I now run `dotnet format`, the `using Path.To.My.Generated.Code` gets removed becasue our style removes unused using.
Therefore code doesnt compile anymore becasue the using is then missig.

## System information:
- Our Code generator uses the [CSharp 4.6 package](https://www.nuget.org/packages/Microsoft.CodeAnalysis.CSharp/4.6.0)
- And we have dotnet SDK 7.0.401 installed in our client

Are analyzers not run? Or do I have to register my analyzer in an additional place?

If any other infos are required tell me.