[orca-list] aria-label on links not read by Orca

[Alex ARNAUD <alexarnaud hypra fr>]

Hello all,

Environment:
- Debian sid
- Firefox 59
- Orca master

Steps to reproduce:
1) Open Firefox
2) Paste this content on the URL bar: data:text/html, <a 
href="taxhike.html" aria-label="Read more about Seminole tax hike">[Read 
more...]</a>
This content comes from: 
https://www.w3.org/WAI/GL/wiki/Using_aria-label_for_link_purpose#Examples

Result: Orca reads "Read more..."
Expected results: Orca should read "Read more about Seminole tax hike"

The final use case is to make image links (without img) readable by Orca 
with aria-label. For example: <a class="icon-thumbs-up" title="Accept 
translation" style="" id="gwt-debug-target-0-accept"></a>
I assume adding aria-label should make the link readable by Orca.

Best regards.
--
Alex ARNAUD
Visual-Impairment Project Manager
Hypra - "Humanizing technology"