Firefox using align instead of text-align

It seems that the `align` attribute is not supported in HTML5. Any reason why is this applied when aligning text within the editor. Looks like in Chrome/Safari it is applying the style attribute with a text-align value, instead. Thanks for any input.

Reproduce text alignment in the editor with Firefox, then compare the generated markup or styling with Chrome and Safari. Confirm which alignment behavior should be consistent across browsers and document the result with a regression check; done means aligned text uses the intended HTML5-compatible behavior in all three browsers.

Written by the indexing model from the issue text.