## Summary
- Document the `stable`/`preview`/`nightly` top-level keys that let
users scope settings overrides per release channel.
- Provide an example `settings.json` snippet and call out that overrides
replace array values rather than merging them.
- Mention that UI-driven changes edit the root config so per-channel
blocks might need manual updates.

## Testing
- Not run (docs only).

Fixes #40458.

Release Notes:

- N/A

---------

Co-authored-by: MrSubidubi <finn@zed.dev>