[Proposal] role=“subheading” and obsolete <hgroup>

What is this?

The subtitle for its parent heading element. Only phrasing contents excluding embedded content “in one heading content” are available. Original thought

Example

Default

<h1>title <span role="subheading">and subtitle</span></h1>

and it can be in one heading element.

<h1>title<br>
<span role="subheading">and subtitle</span><br>
<span role="subheading">and subtitle</span><br>
...</h1>

Reason for proposal

<hgroup> took care of sub heading but failed. So, it might a solution to substitute <hgroup> element.