Accessibility: Conduct a11y review of Spotlight core

[caaster]

Issue Description - WCAG standard

Although institutions such as Stanford have conducted an a11y review of their local Spotlight instance, to date there has not been an a11y review of Spotlight core. Conducting a review will help us be more confident about our a11y work to date, and pinpoint any areas that still require a11y work.

Method of discovery

Siteimprove, Wave, keyboard navigation, VoiceOver etc.

Steps to Reproduce

Suggested solution