FR: Provide a JSON Schema for `.swift-format`

[jasikpark]

BiomeJS provides a JSON Schema with their configuration file:

{
  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
  "formatter": {
    "enabled": false
  },
  "linter": {
    "enabled": false
  },
  "organizeImports": {
    "enabled": false
  }
}

It would be great to have that for swift-format, in addition to separating out the formatting and linting rules more clearly and allowing to disable one or the other entirely as you can in their configuration file.

The main ask is just for the schema file though.

[ahoppen]

Synced to Apple’s issue tracker as rdar://144825229

[allevato]

Someone started contributing this in #747, but it looks like that PR has stalled.