Supabase CLI Docs Incorrectly Reference `Inbucket`; Should Be `Local_smtp` With Mailpit

After Supabase CLI PR #5333 replaced the `inbucket` service with `local_smtp` using Mailpit, the configuration documentation was not updated to reflect the new key and service reference.

1. Open https://supabase.com/docs/guides/local-development/cli/config#local-development-config 2. Observe that the configuration reference still lists `inbucket` instead of `local_smtp`. 3. Attempt to configure email testing locally using the documented `[inbucket]` block; the new CLI ignores this block and starts `local_smtp` instead, leading to unexpected behavior.

Replace the outdated `[inbucket]` documentation section with the corrected `[local_smtp]` configuration block. This aligns the docs with the CLI change and provides users with the correct key and a link to Mailpit for local email testing.

This is a documentation-only fix and has no direct runtime risk. However, users who have copied the old `[inbucket]` snippet into an existing `config.toml` may find that their email testing settings are silently ignored by the newer CLI. The new CLI expects `local_smtp`; if a user reverts to an older CLI version, the old `inbucket` key may be required. To safely rollback, keep a backup of any original config and ensure the CLI version matches the documented key. Also verify the SMTP port (default 54325) aligns with your local setup.