[Feature] Generate and publish JSON Schema for Clippy Config

[JP-Ellis]

It would be really nice to create and publish a JSON schema for the Clippy configuration file. By having a schema definition, a number of editors will automatically provide a much nicer developer experience by validating the configuration and providing little perks like auto-completion.

There are already a few Rust-related schemas published on the JSON Schema Store:

• rustfmt
• cargo

and for other examples of TOML files being published:

• pyproject: for Python projects
• ruff: a Python linter/formatter written in Rust
• uv: a Python package and version manager written in Rust

I think it might be possible to look at how ruff and uv have implemented this and adapt it to Clippy.

If that's something you want to go ahead with, I might be able to have a look into creating a PR.