Is your feature request related to a problem? Please describe.

I'm working on a template for an ASP.NET gRPC project. The template includes ".proto" files with package names using snake_case, such as package my_greeter. I would like to be able to replace this with another symbol when generating a project using dotnet new.

I can see that Value Forms might be able to help with my use case, but it does not currently support snake case. Please consider my request to add snake case as a value form.

Describe the solution you'd like.

Add a new Value Form to support snake_case, for instance:

snakeCase - Converts the value to snake case using the casing rules of the invariant culture.

"forms": {
    "snake": {
      "identifier": "snakeCase"
    }
}

I believe this could be implemented in a similar way to kebabCase as per KebabCaseValueFormFactory.

Additional context

No response