(FED) Screen reader checkbox label

[KirstyScott]

Given a screen reader user is navigating a form.

When the navigate onto a checkbox.

Then the screen label is announced as 'checkbox', without an accessible name to describe the purpose of the checkbox.

Tested on https://www.visitscotland.com/newsletter

JAWS is pulling through the static text next to the checkbox, on that form that is 'Yes, I confirm that the above statements apply'.

NVDA is not pulling through static text, and reading out the gerneric 'checkbox'.

(Note NVDA is picking up the name of the recaptcha checkbox, so this isn't a limitation with NVDA)

Though I can see aria-described has been used to announce the tooltip, these announcements are not coming through.

Best practice would be to ensure the checkbox itself has an accessible name.

[KirstyScott]

VSD-117

[MichaelGrahamVS]

relates to #136