The pre-footer component should allow paragraphs or other kind of markups

[deniak]

Describe the issue
The pre-footer component is great to add additional content at the end of a page. However, it only seems to work with a list of <div>s containing a title and links, e.g.

<div>
    <h2 class="txt-jupiter">Keep updated</h2>
    <a href="mailto:[email protected]?subject=subscribe">Get press releases by email</a>
</div>
<div>
    <h2 class="txt-jupiter">Contact us</h2>
    <a href="mailto:[email protected]">Write to the W3C comms team</a>
</div>

This can be problematic if we want to use paragraphs or other tags because:

1. the pre-footer children don't take all the space available. The width is limited for the selector .pre-footer.l-switcher > * > *
2. all the links in the pre-footer have a display: block; causing them to be on separate lines (see below)

[vivienlacourba]

@NicolaSaunders to give you some context @deniak is working on creating a Jekyll theme based on the W3C design system that we will be use to style sub-sites relying on GitHub pages and a common need we identified is that while we would want to keep the main footer as is we would like to give sub-site owners the possibility to easily add content at the end of their pages within a "pre-footer".