[accessibility] Repetitive instructions for memorable date fields #14112

The issue

As of USWDS 3.14.0, they recommend giving each field of the memorable date component its own instruction text, rather than repeating the group instruction text for each field. See this USWDS PR: uswds/uswds#6725. They also recommend avoiding month options with leading numbers (01 - January), which USWDS removed in 3.9.0 because dual number/name labels confused screen reader users.

As an example of per-field hints, they recommend:

In CiviForm, our date fields have no format hint at all. The description for each of the three fields is the question help text the admin wrote. If the admin left it blank, the element is empty and nothing is announced. There's no fallback text and, even when there is admin-provided help text, it may not address formatting.

Another issue with using the group help text for each of the individual fields is that, if the help text is long, that text will be repeated four times, once on entering the group, and then once for each field.

Definition of Done

• UX has decided if we want to stop repeating the help text on each field since it's already announced at the group level.
• UX has decided if we want to add the per-field formatting hints.
• UX has decided if we want to update our month options not to include the leading numbers.
• Once UX has decided and recorded the decisions, this ticket is passed on to engineering for implementation.