ally/query/focusable does not find a > img[ismap] elements

[rodneyrehm]

Internet Explorer 10-11 and MS Edge consider the <img> element in the following snippet keyboard focusable ("tabbable") - no other browser does this.

<a href="http://example.org">
  <img ismap src="…">
</a>

<!-- img remains keyboard focusable, a does not -->
<a href="http://example.org" tabindex="-1">
  <img ismap src="…">
</a>

[rodneyrehm]

is/focusable will correctly identify the element as focusable, if that's the browser's native behavior. query/focusable in "quick" mode (default) will not find this element, "strict" mode will.