Typeset removing closing slash on void (singleton) elements

[Void elements](https://w3c.github.io/html-reference/syntax.html#syntax-elements), or singletons, like `img`, `hr`, `br` and others contain a closing forward slash in (X)HTML validation, e.g. ``.

When Typeset processes content with HTML, it is removing those closing slashes, e.g. rendering the above as ``.

Closing slashes are of course optional, but:

a) I don't think Typeset should be messing with tag syntax in the first place.
b) In HTML emails, using closing slashes is recommended for cross-email compatibility in all their crappy rendering engines.
c) In my case, I'm using MJML, which uses void/singleton elements for things like [`mj-image`](https://documentation.mjml.io/#mj-image) -- and in that case a tag without a closing slash isn't valid.

My specific use might be an edge case, but I'm sure I'm not the only one formatting HTML emails.

Can Typeset avoid changing HTML tags?