fix(schema): resolve linting issues in nodemon.json schema

[Karan-Palan]

Description

This PR addresses the following linting issues in the nodemon.json schema:

• Removed unknown keywords without x- prefix: Adjusted the schema to ensure compatibility with future versions of JSON Schema, which will refuse to evaluate unknown keywords without the x- prefix.
• Resolved $ref sibling keyword issues: Removed or adjusted sibling keywords to $ref that are not evaluated in Draft 7 and older dialects.

These changes were made to ensure compliance with JSON Schema standards and to resolve the reported linting errors. The schema was updated using the jsonschema lint --fix command

Screenshots

Before and after:

Note

I, along with Juan (JSON Schema TSC member) are defining linting rules for JSON Schema as a Part of a GSoC (Google Summer of code) project here - https://github.com/Karan-Palan/JSON-Schema-Linting, and implementing their auto-fixes here - https://github.com/sourcemeta/jsonschema/blob/main/docs/lint.markdown. We have recently added many rules prefixing unknown keywords with x- which will be introduced in the newer JSON Schema drafts
If beneficial to the project, I suggest integrating the linter with it to write the best schemas and catch any errors and follow best practices. Example of an integration - https://github.com/krakend/krakend-schema/blob/main/.github/workflows/validate-json-schema.yml#L10

[github-actions]

Thanks for the PR!

This section of the codebase is owned by @madskristensen and @hyperupcall - if they write a comment saying "LGTM" then it will be merged.

[Karan-Palan]

The validation fails because AJV ran in strict mode and isn't fully compliant with JSON Schemas, ref - https://youtu.be/wJ7bK22n3IU?si=IOaTDkIGaP5EZ4HY&t=542

[hyperupcall]

Thanks! Supporting more validators has been on my todo for a while: #3570. Unfortunately I won't be able to merge these until that is done. Is adding an alternative implementation something you would be interested in? If so, I can construct a list of more specific requirements or behaviors and maybe we can go from there