doc: remove style for empty links

Fix the side effect when hovering over empty anchor links:

It appears on a few pages:

• async_hooks.html
• cli.html
• deprecations.html EDIT: Taken care of in #34955
• errors.html

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Refs: https://github.com/nodejs/node/pull/34955