Add Support to link multi c# script files together for dotnet 10

[ModxVoldHunter]

let's say, I have 2 C# files that are scripts and i want to link them together, and let's say since it's a script, we could use the reference that usually gives a error "this is only allowed in scripts", now you can use it in an script which means that it can be used now instead of it giving an error.

#r "src/Example2.cs"

using System;

public static class Script {
   public static void Main(string[] args) {
      Console.WriteLine(Example2.ExampleString);
   }
}

this feature could be useful for people who are making projects with different languages and need a few connected c# scripts to complete.

[huoyaoyuan]

A script is a standalone executable unit. Once there are multiple files, a project is more appropriate.

Another case is a lot of entry points with some shared common code. In this case, I think making the shared part a regular project would be better.

[jnm2]

Multi-file support is "postponed for .NET 11": https://github.com/dotnet/sdk/blob/main/documentation/general/dotnet-run-file.md#multiple-c-files

[ModxVoldHunter]

Why? I'm kinda curious.

[CyrusNajmabadi]

far too large and complex for the time available.