[Announcements] A11y/UX: Allow for tabs in global announcements

[d_j_corbin]

The tabs solution does not work in global announcements, regardless of the discussions redesign feature preview being on or off. At our university we need to send global announcements in two languages, and the tabs solution + adding lang attributes would be a better way to better organize bilingual content and help it meet accessibility requirements.

Here is the code I used when testing (which works fine in classic discussions and announcements, but not in the redesign or in global announcements):

<div class="enhanceable_content tabs">
<ul>
<li><a lang="no" href="#fragment-1">Norsk</a></li>
<li><a lang="en" href="#fragment-2">English</a></li>
</ul>
<div id="fragment-1" lang="no">
<h2>HEADER FOR NORSKVERSJONEN</h2>
<p>PLASSER INNHOLDET FOR NORSKVERSJONEN HER.</p>
</div>
<div id="fragment-2" lang="en">
<h2>HEADER FOR ENGLISH VERSION</h2>
<p>PUT THE CONTENT FOR THE ENGLISH VERSION HERE.</p>
</div>
</div>