Gradient selector and color links lack ARIA labels

[SteelWagstaff]

We recently worked with the Inclusive Design Research Centre to conduct an accessibility audit on our WordPress-based software backend (for Pressbooks). In the course of that audit, the auditor indicated that the content of the color picker is not communicated to users of assistive technologies. For example, the selector within the gradient is communicated as link, and the various colors (black, white, red, etc.) are announced as group.

Our auditors indicated that this can be fixed by adding an ARIA label to each color so that it says something other than 'group' (i.e. the color's name or hex value).