Support `workspace/didChangeConfiguration` for `ruff server`

[dhruvmanila]

Tracking issue to add support for workspace/didChangeConfiguration for ruff server.

Related issue in ruff-lsp: https://github.com/astral-sh/ruff-lsp/issues/42

This is a low priority feature for now.

Todo

• [ ] Implement in https://github.com/astral-sh/ruff/blob/84e87771cba841c08ac7d5d1017050b8bd22837e/crates/ruff_server/src/server/api/notifications/did_change_configuration.rs
• [ ] Update Neovim documentation to suggest using the settings key instead of init_options

[snowsignal]

I think this is a duplicate of https://github.com/astral-sh/ruff/issues/10797, but I'll close the former since this has a more through description.