Support file base name substitution in `module` configuration in `launch.json`

Environment data

• VS Code version: 1.33.0
• Extension version: 2019.3.6558
• Python version: Python 3.6.7 (miniconda)

Feature Suggestion

It would be great to be able to debug arbitrary files as modules without having to hardcode their path in launch.json. The best I could find was the following which at least allows to debug any file in a given directory as module.

{
  "configurations": [
    {
      "name": "Python: Module",
      "type": "python",
      "request": "launch",
      "module": "src.nn.models.${fileBasenameNoExtension}"
    }
  ]
}

Not sure if this can be done by the Python extension or would have to be implemented by VS Code itself, but basically I'm suggesting something similar to ${fileBasenameNoExtension} that returns the full dotted "path" to a file from a project's root?