feat: Review test evidence and update accessibility statement

[htmlandbacon]

What

We should use the latest internal accessiblity spreadsheets to do an accessiblity pass and update our accessiblity statement

Why

Our last update was 23 June 2022, and WCAG 2.2 compliance is due in October.

Done when

Updated accessibility compliance documentation

• WCAG 2.2 document
• Mac Test tooling

Other tasks

• Supplied output to DWP accessibility team
• Resolved any issues (WCAG)
• Resolve Issues (Mac tooling)
• Updated accessibility statement

Outcomes

We have an updated accessibility statement with test evidence.

Who needs to know about this

for audit @mitz-lad @claireduxs76

for content update @martinwake

Anything else

• https://www.w3.org/TR/WCAG22/

[htmlandbacon]

Will put out the updates for review.

Then assume we can update the WCAG documents before we do the Macbook testing.