…#9714)

## What

Corrects the `tsconfig` auto-discovery documentation to match how Rolldown actually resolves `tsconfig.json` since v1.1.0.

## Why

The v1.1.0 release notes covered the in-config reference changes (oxc-resolver #1151 reference priority, #1198 allowJs) but omitted [oxc-resolver #1154](oxc-project/oxc-resolver#1154) ("walk past a tsconfig that doesn't claim the file"), which shipped in oxc_resolver v11.19.2 and is part of the 11.19.1 -> 11.21.0 upgrade.

As a result the docs still described the old behavior:

- "find the nearest tsconfig.json"
- "if no referenced project includes the file, fall back to the root tsconfig"

Both are inaccurate now. `find_tsconfig_auto` walks up ancestor directories, uses the first tsconfig that owns the file (its `files`/`include`/`exclude`, or a matching `references` entry), and falls back to the outermost (topmost) tsconfig when nothing claims it. This matches TypeScript 6.0 tsserver. A solution-style root (`files: []` plus only `references`) never claims files on its own, so resolution continues upward unless one of its references matches.

## Changes

- Rewrite the auto-discovery paragraph: upward, ownership-based search with topmost fallback instead of "nearest".
- Fix the references paragraph: root's own `include` vs. a solution-style root, first matching reference wins, per-project `allowJs`.
- Drop the "(similar to Vite)" qualifier; the semantics follow TypeScript, not Vite.
- Add a `::: warning` callout flagging the v1.1.0 behavior change.