Pass Eslint validations: Menu example

Problem/Motivation

At 📌 [Meta] Pass Eslint validations Active we are aiming to have all the eslint validation checks passing for the Examples module.

On this issue, we'll be focused on the menu_example sub-module

Initial errors detected by 27/01/2024

/modules/menu_example/menu_example.links.menu.yml
  24:1  error  Expected indentation of 2 spaces but found 3 spaces  yml/indent
  24:4  error  Expected line before comment                         lines-around-comment
  24:4  error  Expected space or tab after '/*' in comment          spaced-comment
modules/menu_example/menu_example.routing.yml
  97:5  error  Expected line before comment  lines-around-comment
modules/menu_example/menu_example.services.yml
  7:7  error  Expected line before comment  lines-around-comment

Proposed resolution

1. Check the parent issue for detailed instructions about how to run eslint locally
2. Run eslint against the submodule: menu_example
3. Fix the issues found and make a MR with the fixes.