[Rules] revised allowed roles for <img alt=something> #392
Description
an <img> with an accessible name alt=something (or aria-label/labelledby) should only allow a subset of ARIA roles to be applied.
ARIA in HTML img alt=something
test case
allowed roles:
button, checkbox, link, menuitem, menuitemcheckbox, menuitemradio, option, progressbar, radio, scrollbar, separator, slider, switch,tabor treeitem
DPub Role: doc-cover