Inspection for HTML when id starts with # or class starts with .

After searching for 2 hours what my problem is (shame on me, I know) I'd like to suggest another inspection for HTML

If there is something like:

<div id="#foo"></div>

there should be a hint for a malformed id. I'm not sure if this id is valid, but I think nobody wants to use such an id. The same goes with the class attribute and the dot.