Define accessibility best practice guide for Adapt

[kirsty-hames]

Adapt accessibility has been implemented in conformance with WCAG however there is often multiple solutions or conflicting opinions to meeting criteria. In addition, we have interactions/functionality in Adapt that isn't part of standard web leaving it to us as developers to determine the appropriate implementation.

In order to ensure consistency in Adapt and provide support for developers it would be good to document a best practice guide.

I see this having the following uses:

• A resource guide for developing/maintaining Adapt functionality. Including examples of implementation and reasoning for why we've chosen a particular implementation if applicable (e.g. ARIA heading levels vs H tags).
• A resource guide for authoring content in Adapt (e.g how content should read and knowing how to mark it up Update a11y documentation #2553).
• A measure for reviewing where Adapt is now and addressing any inconsistencies (e.g. review use of ARIA holistically rather looking at plugins in isolation).

[oliverfoster]

[oliverfoster]

https://github.com/adaptlearning/adapt_framework/issues/3357 Slider Slider forms mode

[oliverfoster]

#2553 (comment) Zero width spacing