`extend` in generic function with parens split across lines breaks syntax highlighting

JavaScript and TypeScript Nightly version:

Not using that extension, but here's my VSCode info:

Version: 1.97.2 (Universal)
Commit: e54c774e0add60467559eb0d1e229c6452cf8447
Date: 2025-02-12T23:20:35.343Z
Electron: 32.2.7
ElectronBuildId: 10982180
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Darwin arm64 24.3.0

Code

const echo = <T extends number>(a
) => { 
  return a;
};

produces:

Where return is colored incorrectly.

It works fine without the extend:

Notably, this breaks the highlighting for the rest of the file.

Start by reproducing the provided TypeScript snippet in VS Code and inspect the grammar rules handling generic function type parameters, the multiline parenthesized parameter list, and the arrow body. The issue is done when return and the rest of the file receive correct syntax highlighting for this form, without breaking the existing case where the parameter list stays on one line.