Map link with direct click listener to link

[cookiecrook]

From this related issue:

For HTML and SVG, Chromium seems to use Link role for <a> element without href, as long as it has mouse event listeners:
[…trimmed reply…]
(I haven't checked other browsers).

Originally posted by @fred-wang in #39

Later @twilco confirmed this is also aligned with Gecko and WebKit, so the HTML-AAM should update, too.

Note that the implementations are (or should be) limited to direct listeners, not delegated listeners on ancestor elements like the body.

[spectranaut]

@rahimabdi can I assign this to you? Edit: lola just volunteered!

[lolaodelola]

The spec doesn't specify elements with/without event listeners; should this just be changing the a (no href attribute) from generic role to link role?

Just to note, running a quick test in Safari, Chrome and Firefox, <a href=""> with no click event also returns link role. My draft PR reflects this.

[cookiecrook]

Do we need another (or broader) rule like "any otherwise generic leaf node with a click handler" should be exposed as a button?