Update alt tags and Showcase header on home.md

[finekatie]

We propose removing alt text from website screenshots, as the images are decorative. The links to the sites are what's important. This was discussed with content and a11y team.

We also propose changing the title on that section from "Showcase" to "Sites built with USWDS". It's clearer than Showcase.

Summary

Removing alt tags from website screenshots and changing header on home page to make clearer.

Related issue

Closes #2469

Preview link

Preview link: https://federalist-ead78f8d-8948-417c-a957-c21ec5617a57.sites.pages.cloud.gov/preview/uswds/uswds-site/kf-homepage-showcase-tags/

[amyleadem]

Looks good to me! I've added @alex-hull and @amycole501 as reviewers just so that they can confirm the direction here. I also added a comment for them regarding the aria-label on the wrapping section.

[amycole501]

We did discuss these changes and the H2 will be much clearer so the region ARIA could easily be removed to reduce redundancy. Most AT users will be navigating using heading levels most likely anyway.

The screen shot image descriptions aren't adding much in the way of context so reducing the wordiness of the page should improve usability for screen reader users. The links to the example sites are what's important for context.

[thisisdano]

If the accessibility team thinks this is better, then I approve.

[thisisdano]

Getting the following issue in Circle:

Errors in http://localhost:4000/:

 • All page content must be contained by landmarks
   (https://dequeuniversity.com/rules/axe/3.5/region?application=axeAPI)

   (html > body > section:nth-child(7))

   <section class="usa-section bg-base-lightest showcase"> <div
   class="grid-container">...</section>

[mahoneycm]

Pa11y error

Getting the following issue in Circle:

Errors in http://localhost:4000/:

 • All page content must be contained by landmarks
   (https://dequeuniversity.com/rules/axe/3.5/region?application=axeAPI)

   (html > body > section:nth-child(7))

   <section class="usa-section bg-base-lightest showcase"> <div
   class="grid-container">...</section>

It looks like this is happening because this <section> exists outside of an html landmark. For some reason adding the aria-label seems to cause the test to pass.

This <section> is a sibling of the <main> element but should probably be a child

[thisisdano]

This PR also had some broken links that were causing errors.

• I replaced old references to Federalist with new links and references to GitHub Pages
• I replaced a broken link in the Pronouns pattern references section with an archived link to the page on archive.org.
• Updated the changelog for the Pronouns pattern to document the link replacement

cc @annepetersen I think this should be our SOP for broken reference links we find in the future

[thisisdano]

Merging over false positives