The documentAbbrIsUsed test is buggy

[AnnaTomanek]

I tried to enable the documentAbbrIsUsed test on the new AC sample for CKEditor SDK, and it reports a warning for the following source:

<p>1) <strong>Intuitive user interface</strong> optimized for quick problem solving.<br />
2) Flexibility allowing you to use the <strong>accessibility checking engine</strong> of your choice.<br />
3) <strong>Quick Fix</strong> feature letting you fix common problems fully automatically.</p>

It does not help that this test marks an entire block as faulty instead of an inline element that is wrong - since <abbr> is an inline element, we should rather mark just the offending element and not the entire block.

Also, we might consider adding a Quick Fix for this as it should be relatively simple to implement.