fix/eslint plugin react hooks typescript

[everettbu]

Mirror of facebook/react#36051
Original author: MorikawaSouma

---

• fix(compiler): preserve HTML entities in JSX text by correctly detecting non-empty lines
• fix(eslint-plugin-react-hooks): fix TypeScript types for flat config

[greptile-apps]

Greptile Summary

This PR contains two targeted fixes mirrored from facebook/react#36051:

• Compiler: Preserve HTML entities in JSX text — Fixes trimJsxText in BuildHIR.ts to use .trim().length > 0 instead of a regex /[^ \t]/ for detecting non-empty lines. The old regex was not correctly identifying lines containing only certain whitespace characters, which could cause lastNonEmptyLine to be tracked incorrectly, leading to HTML entities being stripped. A test fixture (jsx-html-entity.js) validates the fix.
• ESLint plugin: Fix TypeScript types for flat config — Corrects the ReactHooksFlatConfig type which previously had plugins: {react: any} (wrong key and any type) to plugins: {'react-hooks': typeof plugin}. Also restructures the code to inline configs into the plugin object and use a self-referential assignment pattern, improving type safety and eliminating Object.assign.

Confidence Score: 5/5

• This PR is safe to merge — both changes are minimal, correct bug fixes with no risk of regressions.
• Both changes are small, targeted fixes for clear bugs (incorrect regex for whitespace detection and wrong TypeScript type key/value). The compiler fix has a corresponding test fixture validating correctness. The ESLint plugin fix corrects an obvious type error (react → react-hooks, any → typeof plugin) and the restructuring is a straightforward refactor that preserves runtime behavior.
• No files require special attention.

Important Files Changed

Filename	Overview
compiler/packages/babel-plugin-react-compiler/src/HIR/BuildHIR.ts	Replaces regex /[^ \t]/ with .trim().length > 0 for detecting non-empty lines in JSX text trimming, correctly handling HTML entities and edge-case whitespace. Minimal, correct fix.
packages/eslint-plugin-react-hooks/src/index.ts	Fixes TypeScript types for flat config: corrects ReactHooksFlatConfig.plugins key from react to react-hooks, types it as typeof plugin instead of any, and restructures to inline configs into the plugin object using the standard self-referential pattern.

_{Last reviewed commit: 44c7c5c}