Throw warning/errors when an custom element isn't closed with the proper tag

[ludoboludo]

Is your feature request related to a problem? Please describe.

We had an instance in Dawn where theme check didn't pick up on an custom element being closed with the wrong tag.

Here is the scenario:

<slideshow-component>
  ...
</slider-component>

Describe the solution you'd like

I wonder if there could be a check around custom elements to make sure the closing tag is using the same name ?

Describe alternatives you've considered

No alternatives, just making sure we review our code for those kind of mistakes.

Additional context

PR that fixed this on Dawn: Shopify/dawn#1981