Fix wrong capture in typescript-ts-mode (bug#60167)

Fix wrong capture in typescript-ts-mode (bug#60167)

An example of the issue could be:

    <Menu.Item>
        {({ active }) => (
          link
            ? <Link to={link}> {text}</Link>
            : <a href="#" onClick={onClick}>{text}</a>
        )}
    </Menu.Item>

Here 'link' as well as a lot of the other constructs inside of the
parenthesized expression will be font-locked with
'font-lock-variable-name-face'.  We only want to capture the
identifier.

* lisp/progmodes/typescript-ts-mode.el
(typescript-ts-mode--font-lock-settings): Make the variable capture
only capture the identifier, and not the whole expression.