chore: improve accessibility of svg links

Now that our SVGs include links, we want to ensure those links are accessible for assistive technologies.

Sort the Docusaurus group before PostCSS group in the SVG itself.
Updates the CSS selector to include focus, not just hover. (For focus, i.e. tab navigation.)
Give both links an appropriate title for screen readers to read when focused.
Removes aria-hidden=true, as these now contain interactable elements.

svg / svgo.dev