Dont include used attributes in suggestions

[sapphi-red]

This PR removes used attributes from suggestions except

• it is class , because :class and class can coexist (same with style)
  • https://eslint.vuejs.org/rules/no-duplicate-attributes.html
• it is a event listener, because it is able to listen to same event by adding modifiers

[sapphi-red]

I rewrote it with Set. I have forgotten about the previous comment... #2565 (comment)