Re: [PATCH v2] docs: rework footer with semantic markup and responsive layout

[Rito Rhymes]

We could use a CSS override if the goal were only to change how
the footer looks. But CSS cannot change the footer's semantics for
accessibility, and that's where a fundamental issue lies.

The default theme renders the footer as a generic `div`, and
`class="footer"` does not give it any semantic meaning. Screen
readers and other accessibility tools do not treat that the same as
a real `<footer>` landmark.

To fix that properly, we need to change the markup, either by
rendering a native `<footer>` element or by adding
`role="contentinfo"` to the existing container. That requires
replacing the footer template/component, not just overriding its CSS.

Since the footer appears on every page, I think it's important to
ensure its a11y-friendly, so it makes sense to fix it at the markup
level rather than just overriding the CSS to be mobile-friendly.

Rito