USWDS-Site: Added memorable date accessibility test page

[RachelCorsino]

Summary

Added accessibility test page for memorable date component

Important

We need to update the changelog date before merge.

Related issue

Closes #2875

Preview link

Memorable date
Memorable date accessibility tests

Testing and review

Follow these steps:

1. Confirm that both the main component page and the accessibility tests page have the correct compliance tag at the top.
2. Confirm that the main component page links to the accessibility tests page in the side navigation.
3. Confirm that the main component page links to the accessibility tests page from the accessibility guidance section.
4. Confirm that the main component page shows the accessibility tests summary.
5. Check that accessibility tests page provides the correct counts for each test status type.
6. Confirm the test checklist summaries and data are accurate.
7. Confirm no visual issues.
8. Confirm there is an appropriate changelog entry on both the main component page and the accessibility tests page.

[mahoneycm]

Looking good! I left a couple potential changes related to past and present criterion discussions. Might need some feedback from the team before we move forward

[amyleadem]

Looking good! Thanks for taking this on @RachelCorsino. Just a couple small tweaks and questions below.

Edit: Can you also resolve the merge conflicts in this PR?

[mahoneycm]

Looking good! One small polish change and this should be good to go

[mahoneycm]

Great work! Thanks!

[amyleadem]

LGTM! Thanks for this @RachelCorsino.

@amycole501 and/or @alex-hull, can you review?

[amycole501]

LGTM!

[finekatie]

looks good to me

[annepetersen]

LGTM; added changelog date

[annepetersen]

Couple 404s are showing up in HTML proofer if maybe @RachelCorsino could take a look:

For the Links > External check, the following failures were found:

• At ./_site/documentation/getting-started-for-developers/index.html:2846:

  External link https://nodejs.org/en/download/ failed (status code 404)

• At ./_site/documentation/getting-started/developers/phase-one-install/index.html:2944:

  External link https://nodejs.org/en/download/ failed (status code 404)

[mejiaj]

@RachelCorsino can you fix indents? There should also be an empty line at the end of files.

Indents fixed