JSON schema for the gen-tool format

[robinlindh]

Would be nice to add a JSON schema file for easy syntax highlighting and completion (e.g. in cursor / vscode). I suspect it could be mostly autogenerated as a one-off from the readme file where you already specify the format in detail.

[jnkvca]

@robinlindh I turned this into an actual issue #84 - currently low priority but feel free to bump it up if you think it's more important
(also related to #85 for missing enum doc which will also need a JSON schema)

[AdamMomen]

@robinlindh Submitted a PR for this feature here.