`schema.json` Workaround for these two JetBrains issues:
- [IDEA-236928 json schema: False positive "Schema validation: Validates to more than one variant" with "oneOf"](https://youtrack.jetbrains.com/issue/IDEA-236928)
- [IDEA-265710 JSON schema validation fails if anyOf is nested in oneOf](https://youtrack.jetbrains.com/issue/IDEA-265710)
There is no material effect on the actual schema validation, as the `oneOf`/`allOf` evaluates only one list entry.
`allOf([1])` is `1`, and `oneOf([1])` is also `1`.
Fixes#847
