Update allowances for wbr and br elements

[scottaohara]

The wbr element presently allows all roles and global aria-* attributes. This was an oversight that will be corrected in the next version of the ARIA in HTML specification.

The allowed roles should now only be none and presentation.
The only allowed aria-* attribute should be aria-hidden.

Additionally, the br element also needs to be updated to remove the allowance for all global aria attributes – instead only allowing for the aria-hidden attribute. This will then match the allowances for the wbr element, described above.

[gezlemon]

Thanks, @scottaohara . I've updated the rules so that only "none" and "presentation" are valid roles, and the only valid aria-* attribute is aria-hidden.

[scottaohara]

thank you very much @gezlemon