Provide example/guidance on using aria-disabled on a w/out href

[scottaohara]

if authors really want to disable links, they can instead do <a role=link aria-disabled=true> as removing the href rather than jumping through all the hoops to try and suppress the various ways one can interact with a link.

[scottaohara]

this update should be accompanied by an example

[scottaohara]

this issue will be partially resolved when #262 is merged. an example what to do instead (e.g., an <a> w/out href used with aria-disabled=true) would need to be made to close this issue.

[stes-acc]

Have you checked possible issues with validators using

<a role=link aria-disabled=true>

with respect to role redundancy warnings?

[scottaohara]

<a> without href allows for any role. <a> without href is not supposed to be exposed as a link, so there's no redundancy here.

[scottaohara]

closing as this work will be picked up in #259