Combination of optional operator and new line breaks syntax higlighting in function arguments

Code

// Syntax hilighting is INCORRECT ❌
const a = async (params?: {
  arg?: string | number;
  arg2?: string | number;
  arg3?: string | number;
}) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const b = async (params: {
  arg?: string | number;
  arg2?: string | number;
  arg3?: string | number;
}) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const c = async (params?: { arg?: string | number }) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const d = async (params: { arg?: string | number }) => {
  return params;
};

Reproduce the issue with the TypeScript examples in the report using the repository's TextMate grammar in a supported editor. Inspect the grammar rules responsible for optional parameters, object-type members, and multiline function arguments. Done means the multiline optional-parameter example receives the same correct highlighting as the other examples.