Remove role="document" from the dialog and add aria-modal="true"

Created by: DavidMacDonald

Current Code

<div class="modal" tabindex="-1" role="dialog">
<div class="modal-dialog" role="document">

Solution code

<div class="modal" tabindex="-1" role="dialog" aria-modal="true">
 <div class="modal-dialog" >

Rational

Document role is only necessary if there role="application" on a parent that overrides screen reader short cut keys. The role="dialog" doesn't do that, so it's fine without it ... see aria-practices example https://w3c.github.io/aria-practices/examples/dialog-modal/dialog.html

aria-modal="true" ensure the screen reader user cannot arrow out of the modal inadvertently and replaces the old technique (not used in bootstrap) of aria-hidden on all background content.