oxlint: Add contribution documentation on the Configuration Schema

[connorshea]

For oxlint, it's not particularly intuitive how the configuration_schema.json file should be updated when changes are made for it/when a contributor wants to modify it.

I struggled for a bit on how to do it, but as far as I can tell the main way to regenerate it is to run the tests with cargo test -p oxc_linter (is there a specific test file to run, and should we maybe make this a command in the justfile?). This should be documented. (This should also probably be added to AGENTS.md?).