Allow calculated values in patterns based on question answers

[coordt]

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

For example, in choosing a license, the pattern might provide the initial choice, but then will want to add additional data based on that choice, like "SPDX", and "license_text".

Describe the solution you'd like.

Provide an additional_context attribute to the Choice

[[questions]]
name = "license"
prompt = "Under what license is this code published?"
type = "str"
choices = [
    { label = "2-Clause BSD License", value = "_bsd-2.jinja", additional_context = [{ spdx = "BSD-2-Clause" }] },
]

Describe alternatives you've considered

No response

Additional context

No response