Update ABlog CSS now that it has better-labeled HTML

[choldgraf]

I noticed that ABlog made a release that added the extra HTML structure to make it much easier to style.

For example: their landing page now has sidebar items that look like:

<div class="ablog-sidebar-item ablog__recentposts">
<h3>
  <a href="blog.html">Recent Posts</a>
</h3>
<ul>
  <li>
    <a href="release/ablog-v0.11-released.html">
      25 July - ABlog v0.11 released
    </a>
  </li>
  ... etc etc
</ul>
</div>

We should update our ABlog CSS to utilize these new HTML classes for more predictable behavior.

[choldgraf]

This one is actually not quite done - as the new release of ABlog will change their CSS classes and we'll need to update again.

[12rambau]

ah sorry I just merged your PR I thought it was good to go

[choldgraf]

No worries! That was just the bulk of the fix but not everything 🙂

[choldgraf]

Note that ablog has made this pre-release so we're now getting warnings in our docs - we should update and attach this to the next release. I can try to do it this weekend since my blog uses this :-)