[Feature request] run script that is in an unsaved file

Ability to configure a default language or default executable in Workspace JSON to run script that is in an unsaved file. I don't want to save multiple test files and then delete them afterwards.

Relevant info:

- I run different versions of AutoHotkey in different workspaces (e.g. AHKV1, AHKV2, AHKV2[a116]...)

- I'm not finding a VS Code language ID for AutoHotkey at your provided link, so I suspect I cannot use DefaultLanguage per `For the default language: It should be set with language id defined in` [VS Code](https://github.com/Microsoft/vscode/tree/master/extensions).
- I'm wondering if an option to set the default executable for unsaved files would resolve this (I can specify AHKV1 executable in AHKV1 Workspace, AHKV2 executable in AHKV2 Workspace...)